refactor(core): rename CoreIsolate to JsRuntime (#7373)

deno_core/
- rename core_isolate.rs to runtime.rs
- rename CoreIsolate to JsRuntime
- rename JSError to JsError
- rename JSStackFrame to JsStackFrame

cli/
- update references from deno_core::CoreIsolate to deno_core::JsRuntime
- rename deno_core::JSError to deno_core::JsError
- rename fmt_errors::JSError to fmt_errors::JsError

22 files changed, 274 insertions, 278 deletions

diff --git a/cli/build.rs b/cli/build.rs
index 40b803979..dcc6b4187 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -4,7 +4,7 @@ mod op_fetch_asset;
 
 use deno_core::js_check;
 use deno_core::BasicState;
-use deno_core::CoreIsolate;
+use deno_core::JsRuntime;
 use deno_core::OpRegistry;
 use deno_core::StartupData;
 use std::collections::HashMap;
@@ -13,7 +13,7 @@ use std::path::Path;
 use std::path::PathBuf;
 
 fn create_snapshot(
-  mut isolate: CoreIsolate,
+  mut isolate: JsRuntime,
   snapshot_path: &Path,
   files: Vec<String>,
 ) {
@@ -32,7 +32,7 @@ fn create_snapshot(
 
 fn create_runtime_snapshot(snapshot_path: &Path, files: Vec<String>) {
   let state = BasicState::new();
-  let isolate = CoreIsolate::new(state, StartupData::None, true);
+  let isolate = JsRuntime::new(state, StartupData::None, true);
   create_snapshot(isolate, snapshot_path, files);
 }
 
@@ -71,7 +71,7 @@ fn create_compiler_snapshot(
     op_fetch_asset::op_fetch_asset(custom_libs),
   );
 
-  let isolate = CoreIsolate::new(state, StartupData::None, true);
+  let isolate = JsRuntime::new(state, StartupData::None, true);
   create_snapshot(isolate, snapshot_path, files);
 }
 
diff --git a/cli/errors.rs b/cli/errors.rs
index 327bcfb58..ffa0b95e4 100644
--- a/cli/errors.rs
+++ b/cli/errors.rs
@@ -3,11 +3,11 @@
 //! There are many types of errors in Deno:
 //! - ErrBox: a generic boxed object. This is the super type of all
 //!   errors handled in Rust.
-//! - JSError: a container for the error message and stack trace for exceptions
+//! - JsError: a container for the error message and stack trace for exceptions
 //!   thrown in JavaScript code. We use this to pretty-print stack traces.
 //! - Diagnostic: these are errors that originate in TypeScript's compiler.
-//!   They're similar to JSError, in that they have line numbers.
-//!   But Diagnostics are compile-time type errors, whereas JSErrors are runtime
+//!   They're similar to JsError, in that they have line numbers.
+//!   But Diagnostics are compile-time type errors, whereas JsErrors are runtime
 //!   exceptions.
 
 use crate::import_map::ImportMapError;
diff --git a/cli/fmt_errors.rs b/cli/fmt_errors.rs
index b2925f625..afbf560d0 100644
--- a/cli/fmt_errors.rs
+++ b/cli/fmt_errors.rs
@@ -103,13 +103,13 @@ fn format_maybe_source_line(
   format!("\n{}{}\n{}{}", indent, source_line, indent, color_underline)
 }
 
-/// Wrapper around deno_core::JSError which provides color to_string.
+/// Wrapper around deno_core::JsError which provides color to_string.
 #[derive(Debug)]
-pub struct JSError(deno_core::JSError);
+pub struct JsError(deno_core::JsError);
 
-impl JSError {
+impl JsError {
   pub fn create(
-    core_js_error: deno_core::JSError,
+    core_js_error: deno_core::JsError,
     source_map_getter: &impl SourceMapGetter,
   ) -> ErrBox {
     let core_js_error = apply_source_map(&core_js_error, source_map_getter);
@@ -118,14 +118,14 @@ impl JSError {
   }
 }
 
-impl Deref for JSError {
-  type Target = deno_core::JSError;
+impl Deref for JsError {
+  type Target = deno_core::JsError;
   fn deref(&self) -> &Self::Target {
     &self.0
   }
 }
 
-impl fmt::Display for JSError {
+impl fmt::Display for JsError {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
     let mut formatted_frames = self.0.formatted_frames.clone();
 
@@ -170,7 +170,7 @@ impl fmt::Display for JSError {
   }
 }
 
-impl Error for JSError {}
+impl Error for JsError {}
 
 #[cfg(test)]
 mod tests {
diff --git a/cli/global_state.rs b/cli/global_state.rs
index 79618b741..6add7b7b4 100644
--- a/cli/global_state.rs
+++ b/cli/global_state.rs
@@ -96,7 +96,7 @@ impl GlobalState {
   }
 
   /// This function is called when new module load is
-  /// initialized by the CoreIsolate. Its resposibility is to collect
+  /// initialized by the JsRuntime. Its resposibility is to collect
   /// all dependencies and if it is required then also perform TS typecheck
   /// and traspilation.
   pub async fn prepare_module_load(
@@ -180,7 +180,7 @@ impl GlobalState {
   }
 
   // TODO(bartlomieju): this method doesn't need to be async anymore
-  /// This method is used after `prepare_module_load` finishes and CoreIsolate
+  /// This method is used after `prepare_module_load` finishes and JsRuntime
   /// starts loading source and executing source code. This method shouldn't
   /// perform any IO (besides $DENO_DIR) and only operate on sources collected
   /// during `prepare_module_load`.
diff --git a/cli/inspector.rs b/cli/inspector.rs
index 9a8693ec7..baaa96ec9 100644
--- a/cli/inspector.rs
+++ b/cli/inspector.rs
@@ -373,10 +373,10 @@ impl DenoInspector {
   const CONTEXT_GROUP_ID: i32 = 1;
 
   pub fn new(
-    isolate: &mut deno_core::CoreIsolate,
+    isolate: &mut deno_core::JsRuntime,
     host: SocketAddr,
   ) -> Box<Self> {
-    let core_state_rc = deno_core::CoreIsolate::state(isolate);
+    let core_state_rc = deno_core::JsRuntime::state(isolate);
     let core_state = core_state_rc.borrow();
 
     let scope = &mut v8::HandleScope::new(&mut **isolate);
diff --git a/cli/js.rs b/cli/js.rs
index 8b19ca6ad..6e6767873 100644
--- a/cli/js.rs
+++ b/cli/js.rs
@@ -13,7 +13,7 @@ pub static UNSTABLE_NS_LIB: &str = include_str!("dts/lib.deno.unstable.d.ts");
 
 #[test]
 fn cli_snapshot() {
-  let mut isolate = deno_core::CoreIsolate::new(
+  let mut isolate = deno_core::JsRuntime::new(
     deno_core::BasicState::new(),
     deno_core::StartupData::Snapshot(deno_core::Snapshot::Static(CLI_SNAPSHOT)),
     false,
@@ -31,7 +31,7 @@ fn cli_snapshot() {
 
 #[test]
 fn compiler_snapshot() {
-  let mut isolate = deno_core::CoreIsolate::new(
+  let mut isolate = deno_core::JsRuntime::new(
     deno_core::BasicState::new(),
     deno_core::StartupData::Snapshot(deno_core::Snapshot::Static(
       COMPILER_SNAPSHOT,
diff --git a/cli/main.rs b/cli/main.rs
index 2e2dc71a2..11b12f3fa 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -79,9 +79,9 @@ use crate::permissions::Permissions;
 use crate::tsc::TargetLib;
 use crate::worker::MainWorker;
 use deno_core::v8_set_flags;
-use deno_core::CoreIsolate;
 use deno_core::Deps;
 use deno_core::ErrBox;
+use deno_core::JsRuntime;
 use deno_core::ModuleSpecifier;
 use deno_doc as doc;
 use deno_doc::parser::DocFileLoader;
@@ -217,7 +217,7 @@ async fn print_file_info(
   {
     output.map = source_map.filename.to_str().map(|s| s.to_owned());
   }
-  let es_state_rc = CoreIsolate::state(&worker.isolate);
+  let es_state_rc = JsRuntime::state(&worker.isolate);
   let es_state = es_state_rc.borrow();
 
   if let Some(deps) = es_state.modules.deps(&module_specifier) {
diff --git a/cli/op_fetch_asset.rs b/cli/op_fetch_asset.rs
index 3becc43d7..c936a9370 100644
--- a/cli/op_fetch_asset.rs
+++ b/cli/op_fetch_asset.rs
@@ -81,7 +81,7 @@ fn get_asset(name: &str) -> Option<&'static str> {
 }
 
 /// Warning: Returns a non-JSON op dispatcher. Must be manually attached to
-/// CoreIsolate.
+/// JsRuntime.
 pub fn op_fetch_asset<H: std::hash::BuildHasher, S>(
   custom_assets: HashMap<String, PathBuf, H>,
 ) -> impl Fn(Rc<S>, BufVec) -> Op {
diff --git a/cli/ops/worker_host.rs b/cli/ops/worker_host.rs
index d2c33f005..83f84064b 100644
--- a/cli/ops/worker_host.rs
+++ b/cli/ops/worker_host.rs
@@ -1,6 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-use crate::fmt_errors::JSError;
+use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::ops::io::get_stdio;
 use crate::permissions::Permissions;
@@ -249,7 +249,7 @@ fn serialize_worker_event(event: WorkerEvent) -> Value {
         }
       });
 
-      if let Ok(js_error) = error.downcast::<JSError>() {
+      if let Ok(js_error) = error.downcast::<JsError>() {
         serialized_error = json!({
           "type": "terminalError",
           "error": {
@@ -271,7 +271,7 @@ fn serialize_worker_event(event: WorkerEvent) -> Value {
         }
       });
 
-      if let Ok(js_error) = error.downcast::<JSError>() {
+      if let Ok(js_error) = error.downcast::<JsError>() {
         serialized_error = json!({
           "type": "error",
           "error": {
diff --git a/cli/source_maps.rs b/cli/source_maps.rs
index c42d3edc9..9f57814d4 100644
--- a/cli/source_maps.rs
+++ b/cli/source_maps.rs
@@ -1,5 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-//! This mod provides functions to remap a deno_core::deno_core::JSError based on a source map
+//! This mod provides functions to remap a deno_core::deno_core::JsError based on a source map
 use sourcemap::SourceMap;
 use std::collections::HashMap;
 use std::str;
@@ -18,13 +18,13 @@ pub trait SourceMapGetter {
 /// find a SourceMap.
 pub type CachedMaps = HashMap<String, Option<SourceMap>>;
 
-/// Apply a source map to a deno_core::JSError, returning a JSError where file
+/// Apply a source map to a deno_core::JsError, returning a JsError where file
 /// names and line/column numbers point to the location in the original source,
 /// rather than the transpiled source code.
 pub fn apply_source_map<G: SourceMapGetter>(
-  js_error: &deno_core::JSError,
+  js_error: &deno_core::JsError,
   getter: &G,
-) -> deno_core::JSError {
+) -> deno_core::JsError {
   // Note that js_error.frames has already been source mapped in
   // prepareStackTrace().
   let mut mappings_map: CachedMaps = HashMap::new();
@@ -67,7 +67,7 @@ pub fn apply_source_map<G: SourceMapGetter>(
     _ => js_error.source_line.clone(),
   };
 
-  deno_core::JSError {
+  deno_core::JsError {
     message: js_error.message.clone(),
     source_line,
     script_resource_name,
@@ -194,7 +194,7 @@ mod tests {
 
   #[test]
   fn apply_source_map_line() {
-    let e = deno_core::JSError {
+    let e = deno_core::JsError {
       message: "TypeError: baz".to_string(),
       source_line: Some("foo".to_string()),
       script_resource_name: Some("foo_bar.ts".to_string()),
diff --git a/cli/tsc.rs b/cli/tsc.rs
index 118dc86ae..ec2a5c43e 100644
--- a/cli/tsc.rs
+++ b/cli/tsc.rs
@@ -7,7 +7,7 @@ use crate::disk_cache::DiskCache;
 use crate::file_fetcher::SourceFile;
 use crate::file_fetcher::SourceFileFetcher;
 use crate::flags::Flags;
-use crate::fmt_errors::JSError;
+use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::module_graph::ModuleGraph;
 use crate::module_graph::ModuleGraphLoader;
@@ -1191,9 +1191,9 @@ async fn create_runtime_module_graph(
 }
 
 /// Because TS compiler can raise runtime error, we need to
-/// manually convert formatted JSError into and ErrBox.
+/// manually convert formatted JsError into and ErrBox.
 fn js_error_to_errbox(error: ErrBox) -> ErrBox {
-  match error.downcast::<JSError>() {
+  match error.downcast::<JsError>() {
     Ok(js_error) => {
       let msg = format!("Error in TS compiler:\n{}", js_error);
       ErrBox::error(msg)
diff --git a/cli/worker.rs b/cli/worker.rs
index ac0ef0d26..9ac3bbead 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -1,14 +1,14 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-use crate::fmt_errors::JSError;
+use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::inspector::DenoInspector;
 use crate::ops;
 use crate::ops::io::get_stdio;
 use crate::startup_data;
 use crate::state::State;
-use deno_core::CoreIsolate;
 use deno_core::ErrBox;
+use deno_core::JsRuntime;
 use deno_core::ModuleId;
 use deno_core::ModuleSpecifier;
 use deno_core::StartupData;
@@ -91,7 +91,7 @@ fn create_channels() -> (WorkerChannelsInternal, WorkerHandle) {
 ///  - `WebWorker`
 pub struct Worker {
   pub name: String,
-  pub isolate: deno_core::CoreIsolate,
+  pub isolate: deno_core::JsRuntime,
   pub inspector: Option<Box<DenoInspector>>,
   pub state: Rc<State>,
   pub waker: AtomicWaker,
@@ -105,7 +105,7 @@ impl Worker {
     startup_data: StartupData,
     state: &Rc<State>,
   ) -> Self {
-    let mut isolate = deno_core::CoreIsolate::new_with_loader(
+    let mut isolate = deno_core::JsRuntime::new_with_loader(
       state.clone(),
       state.clone(),
       startup_data,
@@ -114,10 +114,10 @@ impl Worker {
 
     {
       let global_state = state.global_state.clone();
-      let core_state_rc = CoreIsolate::state(&isolate);
+      let core_state_rc = JsRuntime::state(&isolate);
       let mut core_state = core_state_rc.borrow_mut();
       core_state.set_js_error_create_fn(move |core_js_error| {
-        JSError::create(core_js_error, &global_state.ts_compiler)
+        JsError::create(core_js_error, &global_state.ts_compiler)
       });
     }
 
@@ -235,7 +235,7 @@ impl Future for Worker {
 }
 
 impl Deref for Worker {
-  type Target = deno_core::CoreIsolate;
+  type Target = deno_core::JsRuntime;
   fn deref(&self) -> &Self::Target {
     &self.isolate
   }
diff --git a/core/README.md b/core/README.md
index 94fe29de9..f6b429bb8 100644
--- a/core/README.md
+++ b/core/README.md
@@ -8,9 +8,9 @@ The main dependency of this crate is
 bindings.
 
 This Rust crate contains the essential V8 bindings for Deno's command-line
-interface (Deno CLI). The main abstraction here is the Isolate which provides a
-way to execute JavaScript. The Isolate is modeled as a
-`Future<Item=(), Error=JSError>` which completes once all of its ops have
+interface (Deno CLI). The main abstraction here is the JsRuntime which provides
+a way to execute JavaScript. The JsRuntime is modeled as a
+`Future<Item=(), Error=JsError>` which completes once all of its ops have
 completed.
 
 In order to bind Rust functions into JavaScript, use the `Deno.core.dispatch()`
diff --git a/core/bindings.rs b/core/bindings.rs
index c399f265f..55cb080f6 100644
--- a/core/bindings.rs
+++ b/core/bindings.rs
@@ -1,9 +1,9 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-use crate::CoreIsolate;
-use crate::CoreIsolateState;
 use crate::ErrBox;
-use crate::JSError;
+use crate::JsError;
+use crate::JsRuntime;
+use crate::JsRuntimeState;
 use crate::Op;
 use crate::OpId;
 use crate::ZeroCopyBuf;
@@ -239,7 +239,7 @@ pub extern "C" fn host_import_module_dynamically_callback(
 
   let resolver_handle = v8::Global::new(scope, resolver);
   {
-    let state_rc = CoreIsolate::state(scope);
+    let state_rc = JsRuntime::state(scope);
     let mut state = state_rc.borrow_mut();
     state.dyn_import_cb(resolver_handle, &specifier_str, &referrer_name_str);
   }
@@ -253,7 +253,7 @@ pub extern "C" fn host_initialize_import_meta_object_callback(
   meta: v8::Local<v8::Object>,
 ) {
   let scope = &mut unsafe { v8::CallbackScope::new(context) };
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let state = state_rc.borrow();
 
   let id = module.get_identity_hash();
@@ -273,7 +273,7 @@ pub extern "C" fn host_initialize_import_meta_object_callback(
 pub extern "C" fn promise_reject_callback(message: v8::PromiseRejectMessage) {
   let scope = &mut unsafe { v8::CallbackScope::new(&message) };
 
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
 
   let promise = message.get_promise();
@@ -355,7 +355,7 @@ fn recv(
   args: v8::FunctionCallbackArguments,
   _rv: v8::ReturnValue,
 ) {
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
 
   let cb = match v8::Local::<v8::Function>::try_from(args.get(0)) {
@@ -376,7 +376,7 @@ fn send<'s>(
   args: v8::FunctionCallbackArguments,
   mut rv: v8::ReturnValue,
 ) {
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let state = state_rc.borrow_mut();
 
   let op_id = match v8::Local::<v8::Integer>::try_from(args.get(0))
@@ -443,7 +443,7 @@ fn set_macrotask_callback(
   args: v8::FunctionCallbackArguments,
   _rv: v8::ReturnValue,
 ) {
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
 
   let cb = match v8::Local::<v8::Function>::try_from(args.get(0)) {
@@ -592,8 +592,8 @@ fn format_error(
   args: v8::FunctionCallbackArguments,
   mut rv: v8::ReturnValue,
 ) {
-  let e = JSError::from_v8_exception(scope, args.get(0));
-  let state_rc = CoreIsolate::state(scope);
+  let e = JsError::from_v8_exception(scope, args.get(0));
+  let state_rc = JsRuntime::state(scope);
   let state = state_rc.borrow();
   let e = (state.js_error_create_fn)(e);
   let e = e.to_string();
@@ -684,9 +684,9 @@ fn shared_getter(
   _args: v8::PropertyCallbackArguments,
   mut rv: v8::ReturnValue,
 ) {
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
-  let CoreIsolateState {
+  let JsRuntimeState {
     shared_ab, shared, ..
   } = &mut *state;
 
@@ -712,7 +712,7 @@ pub fn module_resolve_callback<'s>(
 ) -> Option<v8::Local<'s, v8::Module>> {
   let scope = &mut unsafe { v8::CallbackScope::new(context) };
 
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
 
   let referrer_id = referrer.get_identity_hash();
diff --git a/core/core.js b/core/core.js
index bf8052871..b84cb2e99 100644
--- a/core/core.js
+++ b/core/core.js
@@ -170,7 +170,7 @@ SharedQueue Binary Layout
 
   function handleAsyncMsgFromRust(opId, buf) {
     if (buf) {
-      // This is the overflow_response case of deno::Isolate::poll().
+      // This is the overflow_response case of deno::JsRuntime::poll().
       asyncHandlers[opId](buf);
     } else {
       while (true) {
diff --git a/core/errors.rs b/core/errors.rs
index 2ce12689a..3e42fb937 100644
--- a/core/errors.rs
+++ b/core/errors.rs
@@ -110,23 +110,23 @@ impl From<Box<dyn AnyError>> for ErrBox {
   }
 }
 
-/// A `JSError` represents an exception coming from V8, with stack frames and
-/// line numbers. The deno_cli crate defines another `JSError` type, which wraps
+/// A `JsError` represents an exception coming from V8, with stack frames and
+/// line numbers. The deno_cli crate defines another `JsError` type, which wraps
 /// the one defined here, that adds source map support and colorful formatting.
 #[derive(Debug, PartialEq, Clone)]
-pub struct JSError {
+pub struct JsError {
   pub message: String,
   pub source_line: Option<String>,
   pub script_resource_name: Option<String>,
   pub line_number: Option<i64>,
   pub start_column: Option<i64>, // 0-based
   pub end_column: Option<i64>,   // 0-based
-  pub frames: Vec<JSStackFrame>,
+  pub frames: Vec<JsStackFrame>,
   pub formatted_frames: Vec<String>,
 }
 
 #[derive(Debug, PartialEq, Clone)]
-pub struct JSStackFrame {
+pub struct JsStackFrame {
   pub type_name: Option<String>,
   pub function_name: Option<String>,
   pub method_name: Option<String>,
@@ -152,7 +152,7 @@ fn get_property<'a>(
   object.get(scope, key.into())
 }
 
-impl JSError {
+impl JsError {
   pub(crate) fn create(js_error: Self) -> ErrBox {
     js_error.into()
   }
@@ -199,7 +199,7 @@ impl JSError {
         formatted_frames_v8.and_then(|a| a.try_into().ok());
 
       // Convert them into Vec<JSStack> and Vec<String> respectively.
-      let mut frames: Vec<JSStackFrame> = vec![];
+      let mut frames: Vec<JsStackFrame> = vec![];
       let mut formatted_frames: Vec<String> = vec![];
       if let (Some(frames_v8), Some(formatted_frames_v8)) =
         (frames_v8, formatted_frames_v8)
@@ -292,7 +292,7 @@ impl JSError {
               .try_into()
               .ok();
           let promise_index = promise_index.map(|n| n.value());
-          frames.push(JSStackFrame {
+          frames.push(JsStackFrame {
             type_name,
             function_name,
             method_name,
@@ -343,7 +343,7 @@ impl JSError {
   }
 }
 
-impl Error for JSError {}
+impl Error for JsError {}
 
 fn format_source_loc(
   file_name: &str,
@@ -355,7 +355,7 @@ fn format_source_loc(
   format!("{}:{}:{}", file_name, line_number, column_number)
 }
 
-impl fmt::Display for JSError {
+impl fmt::Display for JsError {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
     if let Some(script_resource_name) = &self.script_resource_name {
       if self.line_number.is_some() && self.start_column.is_some() {
diff --git a/core/examples/http_bench_bin_ops.rs b/core/examples/http_bench_bin_ops.rs
index f93b8b079..00eb95f44 100644
--- a/core/examples/http_bench_bin_ops.rs
+++ b/core/examples/http_bench_bin_ops.rs
@@ -4,7 +4,7 @@ extern crate log;
 use deno_core::js_check;
 use deno_core::BasicState;
 use deno_core::BufVec;
-use deno_core::CoreIsolate;
+use deno_core::JsRuntime;
 use deno_core::Op;
 use deno_core::OpRegistry;
 use deno_core::Script;
@@ -77,7 +77,7 @@ impl From<Record> for RecordBuf {
   }
 }
 
-fn create_isolate() -> CoreIsolate {
+fn create_isolate() -> JsRuntime {
   let state = BasicState::new();
   register_op_bin_sync(&state, "listen", op_listen);
   register_op_bin_sync(&state, "close", op_close);
@@ -90,7 +90,7 @@ fn create_isolate() -> CoreIsolate {
     filename: "http_bench_bin_ops.js",
   });
 
-  CoreIsolate::new(state, startup_data, false)
+  JsRuntime::new(state, startup_data, false)
 }
 
 fn op_listen(
diff --git a/core/examples/http_bench_json_ops.rs b/core/examples/http_bench_json_ops.rs
index 6e3063a0f..de467b8ad 100644
--- a/core/examples/http_bench_json_ops.rs
+++ b/core/examples/http_bench_json_ops.rs
@@ -4,8 +4,8 @@ extern crate log;
 use deno_core::js_check;
 use deno_core::BasicState;
 use deno_core::BufVec;
-use deno_core::CoreIsolate;
 use deno_core::ErrBox;
+use deno_core::JsRuntime;
 use deno_core::OpRegistry;
 use deno_core::Script;
 use deno_core::StartupData;
@@ -41,7 +41,7 @@ impl log::Log for Logger {
   fn flush(&self) {}
 }
 
-fn create_isolate() -> CoreIsolate {
+fn create_isolate() -> JsRuntime {
   let state = BasicState::new();
   state.register_op_json_sync("listen", op_listen);
   state.register_op_json_sync("close", op_close);
@@ -54,7 +54,7 @@ fn create_isolate() -> CoreIsolate {
     filename: "http_bench_json_ops.js",
   });
 
-  CoreIsolate::new(state, startup_data, false)
+  JsRuntime::new(state, startup_data, false)
 }
 
 fn op_listen(
diff --git a/core/lib.rs b/core/lib.rs
index f09278b2f..2c70f0f87 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -10,7 +10,6 @@ extern crate log;
 
 mod basic_state;
 mod bindings;
-mod core_isolate;
 mod errors;
 mod flags;
 mod module_specifier;
@@ -19,23 +18,16 @@ mod normalize_path;
 mod ops;
 pub mod plugin_api;
 mod resources;
+mod runtime;
 mod shared_queue;
 mod zero_copy_buf;
 
 pub use rusty_v8 as v8;
 
 pub use crate::basic_state::BasicState;
-pub use crate::core_isolate::js_check;
-pub use crate::core_isolate::CoreIsolate;
-pub use crate::core_isolate::CoreIsolateState;
-pub use crate::core_isolate::GetErrorClassFn;
-pub use crate::core_isolate::HeapLimits;
-pub use crate::core_isolate::Script;
-pub use crate::core_isolate::Snapshot;
-pub use crate::core_isolate::StartupData;
 pub use crate::errors::AnyError;
 pub use crate::errors::ErrBox;
-pub use crate::errors::JSError;
+pub use crate::errors::JsError;
 pub use crate::flags::v8_set_flags;
 pub use crate::module_specifier::ModuleResolutionError;
 pub use crate::module_specifier::ModuleSpecifier;
@@ -55,6 +47,14 @@ pub use crate::ops::OpRegistry;
 pub use crate::ops::OpRouter;
 pub use crate::ops::OpTable;
 pub use crate::resources::ResourceTable;
+pub use crate::runtime::js_check;
+pub use crate::runtime::GetErrorClassFn;
+pub use crate::runtime::HeapLimits;
+pub use crate::runtime::JsRuntime;
+pub use crate::runtime::JsRuntimeState;
+pub use crate::runtime::Script;
+pub use crate::runtime::Snapshot;
+pub use crate::runtime::StartupData;
 pub use crate::zero_copy_buf::BufVec;
 pub use crate::zero_copy_buf::ZeroCopyBuf;
 pub use serde_json;
diff --git a/core/modules.rs b/core/modules.rs
index 7b1e0c5a3..2b914fd1e 100644
--- a/core/modules.rs
+++ b/core/modules.rs
@@ -84,7 +84,7 @@ pub trait ModuleLoader {
   ///
   /// For example implementor might download multiple modules in
   /// parallel and transpile them to final JS sources before
-  /// yielding control back to Isolate.
+  /// yielding control back to the runtime.
   ///
   /// It's not required to implement this method.
   fn prepare_load(
@@ -99,7 +99,7 @@ pub trait ModuleLoader {
 }
 
 /// Placeholder structure used when creating
-/// isolate that doesn't support module loading.
+/// a runtime that doesn't support module loading.
 pub(crate) struct NoopModuleLoader;
 
 impl ModuleLoader for NoopModuleLoader {
@@ -138,8 +138,7 @@ pub enum LoadState {
   Done,
 }
 
-/// This future is used to implement parallel async module loading without
-/// that is consumed by the isolate.
+/// This future is used to implement parallel async module loading.
 pub struct RecursiveModuleLoad {
   kind: Kind,
   // TODO(bartlomieju): in future this value should
@@ -547,7 +546,7 @@ mod tests {
   use super::*;
   use crate::js_check;
   use crate::BasicState;
-  use crate::CoreIsolate;
+  use crate::JsRuntime;
   use crate::StartupData;
   use futures::future::FutureExt;
   use std::error::Error;
@@ -560,7 +559,7 @@ mod tests {
   // even though we are only using poll() in these tests and not Tokio, we must
   // nevertheless run it in the tokio executor. Ideally run_in_task can be
   // removed in the future.
-  use crate::core_isolate::tests::run_in_task;
+  use crate::runtime::tests::run_in_task;
 
   #[derive(Default)]
   struct MockLoader {
@@ -725,17 +724,17 @@ mod tests {
   fn test_recursive_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut isolate = CoreIsolate::new_with_loader(
+    let mut runtime = JsRuntime::new_with_loader(
       loader,
       BasicState::new(),
       StartupData::None,
       false,
     );
     let spec = ModuleSpecifier::resolve_url("file:///a.js").unwrap();
-    let a_id_fut = isolate.load_module(&spec, None);
+    let a_id_fut = runtime.load_module(&spec, None);
     let a_id = futures::executor::block_on(a_id_fut).expect("Failed to load");
 
-    js_check(isolate.mod_evaluate(a_id));
+    js_check(runtime.mod_evaluate(a_id));
     let l = loads.lock().unwrap();
     assert_eq!(
       l.to_vec(),
@@ -747,7 +746,7 @@ mod tests {
       ]
     );
 
-    let state_rc = CoreIsolate::state(&isolate);
+    let state_rc = JsRuntime::state(&runtime);
     let state = state_rc.borrow();
     let modules = &state.modules;
     assert_eq!(modules.get_id("file:///a.js"), Some(a_id));
@@ -792,7 +791,7 @@ mod tests {
   fn test_circular_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut isolate = CoreIsolate::new_with_loader(
+    let mut runtime = JsRuntime::new_with_loader(
       loader,
       BasicState::new(),
       StartupData::None,
@@ -801,10 +800,10 @@ mod tests {
 
     let fut = async move {
       let spec = ModuleSpecifier::resolve_url("file:///circular1.js").unwrap();
-      let result = isolate.load_module(&spec, None).await;
+      let result = runtime.load_module(&spec, None).await;
       assert!(result.is_ok());
       let circular1_id = result.unwrap();
-      js_check(isolate.mod_evaluate(circular1_id));
+      js_check(runtime.mod_evaluate(circular1_id));
 
       let l = loads.lock().unwrap();
       assert_eq!(
@@ -816,7 +815,7 @@ mod tests {
         ]
       );
 
-      let state_rc = CoreIsolate::state(&isolate);
+      let state_rc = JsRuntime::state(&runtime);
       let state = state_rc.borrow();
       let modules = &state.modules;
 
@@ -870,7 +869,7 @@ mod tests {
   fn test_redirect_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut isolate = CoreIsolate::new_with_loader(
+    let mut runtime = JsRuntime::new_with_loader(
       loader,
       BasicState::new(),
       StartupData::None,
@@ -879,11 +878,11 @@ mod tests {
 
     let fut = async move {
       let spec = ModuleSpecifier::resolve_url("file:///redirect1.js").unwrap();
-      let result = isolate.load_module(&spec, None).await;
+      let result = runtime.load_module(&spec, None).await;
       println!(">> result {:?}", result);
       assert!(result.is_ok());
       let redirect1_id = result.unwrap();
-      js_check(isolate.mod_evaluate(redirect1_id));
+      js_check(runtime.mod_evaluate(redirect1_id));
       let l = loads.lock().unwrap();
       assert_eq!(
         l.to_vec(),
@@ -894,7 +893,7 @@ mod tests {
         ]
       );
 
-      let state_rc = CoreIsolate::state(&isolate);
+      let state_rc = JsRuntime::state(&runtime);
       let state = state_rc.borrow();
       let modules = &state.modules;
 
@@ -939,14 +938,14 @@ mod tests {
     run_in_task(|mut cx| {
       let loader = MockLoader::new();
       let loads = loader.loads.clone();
-      let mut isolate = CoreIsolate::new_with_loader(
+      let mut runtime = JsRuntime::new_with_loader(
         loader,
         BasicState::new(),
         StartupData::None,
         false,
       );
       let spec = ModuleSpecifier::resolve_url("file:///main.js").unwrap();
-      let mut recursive_load = isolate.load_module(&spec, None).boxed_local();
+      let mut recursive_load = runtime.load_module(&spec, None).boxed_local();
 
       let result = recursive_load.poll_unpin(&mut cx);
       assert!(result.is_pending());
@@ -989,14 +988,14 @@ mod tests {
   fn loader_disappears_after_error() {
     run_in_task(|mut cx| {
       let loader = MockLoader::new();
-      let mut isolate = CoreIsolate::new_with_loader(
+      let mut runtime = JsRuntime::new_with_loader(
         loader,
         BasicState::new(),
         StartupData::None,
         false,
       );
       let spec = ModuleSpecifier::resolve_url("file:///bad_import.js").unwrap();
-      let mut load_fut = isolate.load_module(&spec, None).boxed_local();
+      let mut load_fut = runtime.load_module(&spec, None).boxed_local();
       let result = load_fut.poll_unpin(&mut cx);
       if let Poll::Ready(Err(err)) = result {
         assert_eq!(
@@ -1022,7 +1021,7 @@ mod tests {
   fn recursive_load_main_with_code() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut isolate = CoreIsolate::new_with_loader(
+    let mut runtime = JsRuntime::new_with_loader(
       loader,
       BasicState::new(),
       StartupData::None,
@@ -1033,13 +1032,13 @@ mod tests {
     // The behavior should be very similar to /a.js.
     let spec =
       ModuleSpecifier::resolve_url("file:///main_with_code.js").unwrap();
-    let main_id_fut = isolate
+    let main_id_fut = runtime
       .load_module(&spec, Some(MAIN_WITH_CODE_SRC.to_owned()))
       .boxed_local();
     let main_id =
       futures::executor::block_on(main_id_fut).expect("Failed to load");
 
-    js_check(isolate.mod_evaluate(main_id));
+    js_check(runtime.mod_evaluate(main_id));
 
     let l = loads.lock().unwrap();
     assert_eq!(
@@ -1047,7 +1046,7 @@ mod tests {
       vec!["file:///b.js", "file:///c.js", "file:///d.js"]
     );
 
-    let state_rc = CoreIsolate::state(&isolate);
+    let state_rc = JsRuntime::state(&runtime);
     let state = state_rc.borrow();
     let modules = &state.modules;
 
diff --git a/core/core_isolate.rs b/core/runtime.rs
index b8922b982..2f574b195 100644
--- a/core/core_isolate.rs
+++ b/core/runtime.rs
@@ -1,10 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-// Do not add any dependency to modules.rs!
-// modules.rs is complex and should remain decoupled from isolate.rs to keep the
-// Isolate struct from becoming too bloating for users who do not need
-// asynchronous module loading.
-
 use rusty_v8 as v8;
 
 use crate::bindings;
@@ -25,7 +20,7 @@ use crate::ops::*;
 use crate::shared_queue::SharedQueue;
 use crate::shared_queue::RECOMMENDED_SIZE;
 use crate::ErrBox;
-use crate::JSError;
+use crate::JsError;
 use crate::OpRouter;
 use futures::stream::FuturesUnordered;
 use futures::stream::StreamExt;
@@ -97,7 +92,7 @@ impl StartupData<'_> {
   }
 }
 
-type JSErrorCreateFn = dyn Fn(JSError) -> ErrBox;
+type JsErrorCreateFn = dyn Fn(JsError) -> ErrBox;
 
 pub type GetErrorClassFn = dyn for<'e> Fn(&'e ErrBox) -> &'static str;
 
@@ -109,16 +104,18 @@ struct IsolateAllocations {
 }
 
 /// A single execution context of JavaScript. Corresponds roughly to the "Web
-/// Worker" concept in the DOM. An CoreIsolate is a Future that can be used with
-/// Tokio. The CoreIsolate future completes when there is an error or when all
+/// Worker" concept in the DOM. A JsRuntime is a Future that can be used with
+/// an event loop (Tokio, async_std).
+////
+/// The JsRuntime future completes when there is an error or when all
 /// pending ops have completed.
 ///
 /// Ops are created in JavaScript by calling Deno.core.dispatch(), and in Rust
 /// by implementing dispatcher function that takes control buffer and optional zero copy buffer
 /// as arguments. An async Op corresponds exactly to a Promise in JavaScript.
-pub struct CoreIsolate {
+pub struct JsRuntime {
   // This is an Option<OwnedIsolate> instead of just OwnedIsolate to workaround
-  // an safety issue with SnapshotCreator. See CoreIsolate::drop.
+  // an safety issue with SnapshotCreator. See JsRuntime::drop.
   v8_isolate: Option<v8::OwnedIsolate>,
   snapshot_creator: Option<v8::SnapshotCreator>,
   has_snapshotted: bool,
@@ -127,15 +124,15 @@ pub struct CoreIsolate {
   allocations: IsolateAllocations,
 }
 
-/// Internal state for CoreIsolate which is stored in one of v8::Isolate's
+/// Internal state for JsRuntime which is stored in one of v8::Isolate's
 /// embedder slots.
-pub struct CoreIsolateState {
+pub struct JsRuntimeState {
   pub global_context: Option<v8::Global<v8::Context>>,
   pub(crate) shared_ab: Option<v8::Global<v8::SharedArrayBuffer>>,
   pub(crate) js_recv_cb: Option<v8::Global<v8::Function>>,
   pub(crate) js_macrotask_cb: Option<v8::Global<v8::Function>>,
   pub(crate) pending_promise_exceptions: HashMap<i32, v8::Global<v8::Value>>,
-  pub(crate) js_error_create_fn: Box<JSErrorCreateFn>,
+  pub(crate) js_error_create_fn: Box<JsErrorCreateFn>,
   pub(crate) shared: SharedQueue,
   pub(crate) pending_ops: FuturesUnordered<PendingOpFuture>,
   pub(crate) pending_unref_ops: FuturesUnordered<PendingOpFuture>,
@@ -150,20 +147,20 @@ pub struct CoreIsolateState {
   waker: AtomicWaker,
 }
 
-impl Deref for CoreIsolate {
+impl Deref for JsRuntime {
   type Target = v8::Isolate;
   fn deref(&self) -> &v8::Isolate {
     self.v8_isolate.as_ref().unwrap()
   }
 }
 
-impl DerefMut for CoreIsolate {
+impl DerefMut for JsRuntime {
   fn deref_mut(&mut self) -> &mut v8::Isolate {
     self.v8_isolate.as_mut().unwrap()
   }
 }
 
-impl Drop for CoreIsolate {
+impl Drop for JsRuntime {
   fn drop(&mut self) {
     if let Some(creator) = self.snapshot_creator.take() {
       // TODO(ry): in rusty_v8, `SnapShotCreator::get_owned_isolate()` returns
@@ -229,7 +226,7 @@ pub(crate) struct IsolateOptions {
   heap_limits: Option<HeapLimits>,
 }
 
-impl CoreIsolate {
+impl JsRuntime {
   /// startup_data defines the snapshot or script used at startup to initialize
   /// the isolate.
   pub fn new(
@@ -308,7 +305,7 @@ impl CoreIsolate {
       let mut creator =
         v8::SnapshotCreator::new(Some(&bindings::EXTERNAL_REFERENCES));
       let isolate = unsafe { creator.get_owned_isolate() };
-      let mut isolate = CoreIsolate::setup_isolate(isolate);
+      let mut isolate = JsRuntime::setup_isolate(isolate);
       {
         let scope = &mut v8::HandleScope::new(&mut isolate);
         let context = bindings::initialize_context(scope);
@@ -335,7 +332,7 @@ impl CoreIsolate {
       }
 
       let isolate = v8::Isolate::new(params);
-      let mut isolate = CoreIsolate::setup_isolate(isolate);
+      let mut isolate = JsRuntime::setup_isolate(isolate);
       {
         let scope = &mut v8::HandleScope::new(&mut isolate);
         let context = if snapshot_loaded {
@@ -350,13 +347,13 @@ impl CoreIsolate {
       (isolate, None)
     };
 
-    isolate.set_slot(Rc::new(RefCell::new(CoreIsolateState {
+    isolate.set_slot(Rc::new(RefCell::new(JsRuntimeState {
       global_context: Some(global_context),
       pending_promise_exceptions: HashMap::new(),
       shared_ab: None,
       js_recv_cb: None,
       js_macrotask_cb: None,
-      js_error_create_fn: Box::new(JSError::create),
+      js_error_create_fn: Box::new(JsError::create),
       shared: SharedQueue::new(RECOMMENDED_SIZE),
       pending_ops: FuturesUnordered::new(),
       pending_unref_ops: FuturesUnordered::new(),
@@ -392,8 +389,8 @@ impl CoreIsolate {
     isolate
   }
 
-  pub fn state(isolate: &v8::Isolate) -> Rc<RefCell<CoreIsolateState>> {
-    let s = isolate.get_slot::<Rc<RefCell<CoreIsolateState>>>().unwrap();
+  pub fn state(isolate: &v8::Isolate) -> Rc<RefCell<JsRuntimeState>> {
+    let s = isolate.get_slot::<Rc<RefCell<JsRuntimeState>>>().unwrap();
     s.clone()
   }
 
@@ -412,8 +409,8 @@ impl CoreIsolate {
   /// Executes traditional JavaScript code (traditional = not ES modules)
   ///
   /// ErrBox can be downcast to a type that exposes additional information about
-  /// the V8 exception. By default this type is JSError, however it may be a
-  /// different type if CoreIsolate::set_js_error_create_fn() has been used.
+  /// the V8 exception. By default this type is JsError, however it may be a
+  /// different type if JsRuntime::set_js_error_create_fn() has been used.
   pub fn execute(
     &mut self,
     js_filename: &str,
@@ -459,8 +456,8 @@ impl CoreIsolate {
   /// set to true.
   ///
   /// ErrBox can be downcast to a type that exposes additional information about
-  /// the V8 exception. By default this type is JSError, however it may be a
-  /// different type if CoreIsolate::set_js_error_create_fn() has been used.
+  /// the V8 exception. By default this type is JsError, however it may be a
+  /// different type if JsRuntime::set_js_error_create_fn() has been used.
   pub fn snapshot(&mut self) -> v8::StartupData {
     assert!(self.snapshot_creator.is_some());
     let state = Self::state(self);
@@ -535,14 +532,14 @@ where
   callback(current_heap_limit, initial_heap_limit)
 }
 
-impl Future for CoreIsolate {
+impl Future for JsRuntime {
   type Output = Result<(), ErrBox>;
 
   fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-    let core_isolate = self.get_mut();
-    core_isolate.shared_init();
+    let runtime = self.get_mut();
+    runtime.shared_init();
 
-    let state_rc = Self::state(core_isolate);
+    let state_rc = Self::state(runtime);
     {
       let state = state_rc.borrow();
       state.waker.register(cx.waker());
@@ -553,7 +550,7 @@ impl Future for CoreIsolate {
       !state.preparing_dyn_imports.is_empty()
     };
     if has_preparing {
-      let poll_imports = core_isolate.prepare_dyn_imports(cx)?;
+      let poll_imports = runtime.prepare_dyn_imports(cx)?;
       assert!(poll_imports.is_ready());
     }
 
@@ -562,12 +559,12 @@ impl Future for CoreIsolate {
       !state.pending_dyn_imports.is_empty()
     };
     if has_pending {
-      let poll_imports = core_isolate.poll_dyn_imports(cx)?;
+      let poll_imports = runtime.poll_dyn_imports(cx)?;
       assert!(poll_imports.is_ready());
     }
 
     let scope = &mut v8::HandleScope::with_context(
-      &mut **core_isolate,
+      &mut **runtime,
       state_rc.borrow().global_context.as_ref().unwrap(),
     );
 
@@ -654,13 +651,13 @@ impl Future for CoreIsolate {
   }
 }
 
-impl CoreIsolateState {
+impl JsRuntimeState {
   /// Allows a callback to be set whenever a V8 exception is made. This allows
-  /// the caller to wrap the JSError into an error. By default this callback
-  /// is set to JSError::create.
+  /// the caller to wrap the JsError into an error. By default this callback
+  /// is set to JsError::create.
   pub fn set_js_error_create_fn(
     &mut self,
-    f: impl Fn(JSError) -> ErrBox + 'static,
+    f: impl Fn(JsError) -> ErrBox + 'static,
   ) {
     self.js_error_create_fn = Box::new(f);
   }
@@ -706,7 +703,7 @@ fn async_op_response<'s>(
 ) -> Result<(), ErrBox> {
   let context = scope.get_current_context();
   let global: v8::Local<v8::Value> = context.global(scope).into();
-  let js_recv_cb = CoreIsolate::state(scope)
+  let js_recv_cb = JsRuntime::state(scope)
     .borrow()
     .js_recv_cb
     .as_ref()
@@ -736,7 +733,7 @@ fn drain_macrotasks<'s>(scope: &mut v8::HandleScope<'s>) -> Result<(), ErrBox> {
   let context = scope.get_current_context();
   let global: v8::Local<v8::Value> = context.global(scope).into();
 
-  let js_macrotask_cb = match CoreIsolate::state(scope)
+  let js_macrotask_cb = match JsRuntime::state(scope)
     .borrow_mut()
     .js_macrotask_cb
     .as_ref()
@@ -790,9 +787,9 @@ pub(crate) fn exception_to_err_result<'s, T>(
     }
   }
 
-  let js_error = JSError::from_v8_exception(scope, exception);
+  let js_error = JsError::from_v8_exception(scope, exception);
 
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let state = state_rc.borrow();
   let js_error = (state.js_error_create_fn)(js_error);
 
@@ -809,7 +806,7 @@ pub(crate) fn exception_to_err_result<'s, T>(
 fn check_promise_exceptions<'s>(
   scope: &mut v8::HandleScope<'s>,
 ) -> Result<(), ErrBox> {
-  let state_rc = CoreIsolate::state(scope);
+  let state_rc = JsRuntime::state(scope);
   let mut state = state_rc.borrow_mut();
 
   if let Some(&key) = state.pending_promise_exceptions.keys().next() {
@@ -843,7 +840,7 @@ fn boxed_slice_to_uint8array<'sc>(
 }
 
 // Related to module loading
-impl CoreIsolate {
+impl JsRuntime {
   /// Low-level module creation.
   ///
   /// Called during module loading or dynamic import loading.
@@ -902,8 +899,8 @@ impl CoreIsolate {
   /// Instantiates a ES module
   ///
   /// ErrBox can be downcast to a type that exposes additional information about
-  /// the V8 exception. By default this type is JSError, however it may be a
-  /// different type if CoreIsolate::set_js_error_create_fn() has been used.
+  /// the V8 exception. By default this type is JsError, however it may be a
+  /// different type if JsRuntime::set_js_error_create_fn() has been used.
   fn mod_instantiate(&mut self, id: ModuleId) -> Result<(), ErrBox> {
     let state_rc = Self::state(self);
     let state = state_rc.borrow();
@@ -938,8 +935,8 @@ impl CoreIsolate {
   /// Evaluates an already instantiated ES module.
   ///
   /// ErrBox can be downcast to a type that exposes additional information about
-  /// the V8 exception. By default this type is JSError, however it may be a
-  /// different type if CoreIsolate::set_js_error_create_fn() has been used.
+  /// the V8 exception. By default this type is JsError, however it may be a
+  /// different type if JsRuntime::set_js_error_create_fn() has been used.
   pub fn mod_evaluate(&mut self, id: ModuleId) -> Result<(), ErrBox> {
     self.shared_init();
 
@@ -965,7 +962,7 @@ impl CoreIsolate {
       // Because that promise is created internally by V8, when error occurs during
       // module evaluation the promise is rejected, and since the promise has no rejection
       // handler it will result in call to `bindings::promise_reject_callback` adding
-      // the promise to pending promise rejection table - meaning Isolate will return
+      // the promise to pending promise rejection table - meaning JsRuntime will return
       // error on next poll().
       //
       // This situation is not desirable as we want to manually return error at the
@@ -1253,7 +1250,7 @@ impl CoreIsolate {
 
   /// Asynchronously load specified module and all of it's dependencies
   ///
-  /// User must call `Isolate::mod_evaluate` with returned `ModuleId`
+  /// User must call `JsRuntime::mod_evaluate` with returned `ModuleId`
   /// manually after load is finished.
   pub async fn load_module(
     &mut self,
@@ -1316,7 +1313,7 @@ pub mod tests {
       }
     }
     panic!(
-      "CoreIsolate still not ready after polling {} times.",
+      "JsRuntime still not ready after polling {} times.",
       max_poll_count
     )
   }
@@ -1407,15 +1404,15 @@ pub mod tests {
     }
   }
 
-  fn setup(mode: Mode) -> (CoreIsolate, Arc<AtomicUsize>) {
+  fn setup(mode: Mode) -> (JsRuntime, Arc<AtomicUsize>) {
     let dispatch_count = Arc::new(AtomicUsize::new(0));
     let test_state = Rc::new(TestOpRouter {
       mode,
       dispatch_count: dispatch_count.clone(),
     });
-    let mut isolate = CoreIsolate::new(test_state, StartupData::None, false);
+    let mut runtime = JsRuntime::new(test_state, StartupData::None, false);
 
-    js_check(isolate.execute(
+    js_check(runtime.execute(
       "setup.js",
       r#"
         function assert(cond) {
@@ -1426,13 +1423,13 @@ pub mod tests {
         "#,
     ));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
-    (isolate, dispatch_count)
+    (runtime, dispatch_count)
   }
 
   #[test]
   fn test_dispatch() {
-    let (mut isolate, dispatch_count) = setup(Mode::Async);
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::Async);
+    js_check(runtime.execute(
       "filename.js",
       r#"
         let control = new Uint8Array([42]);
@@ -1448,8 +1445,8 @@ pub mod tests {
 
   #[test]
   fn test_dispatch_no_zero_copy_buf() {
-    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(0));
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::AsyncZeroCopy(0));
+    js_check(runtime.execute(
       "filename.js",
       r#"
         Deno.core.send(1);
@@ -1460,8 +1457,8 @@ pub mod tests {
 
   #[test]
   fn test_dispatch_stack_zero_copy_bufs() {
-    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(2));
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::AsyncZeroCopy(2));
+    js_check(runtime.execute(
       "filename.js",
       r#"
         let zero_copy_a = new Uint8Array([0]);
@@ -1474,8 +1471,8 @@ pub mod tests {
 
   #[test]
   fn test_dispatch_heap_zero_copy_bufs() {
-    let (mut isolate, dispatch_count) = setup(Mode::AsyncZeroCopy(5));
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::AsyncZeroCopy(5));
+    js_check(runtime.execute(
       "filename.js",
       r#"
         let zero_copy_a = new Uint8Array([0]);
@@ -1492,9 +1489,9 @@ pub mod tests {
   #[test]
   fn test_poll_async_delayed_ops() {
     run_in_task(|cx| {
-      let (mut isolate, dispatch_count) = setup(Mode::Async);
+      let (mut runtime, dispatch_count) = setup(Mode::Async);
 
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "setup2.js",
         r#"
          let nrecv = 0;
@@ -1504,7 +1501,7 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "check1.js",
         r#"
          assert(nrecv == 0);
@@ -1514,9 +1511,9 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "check2.js",
         r#"
          assert(nrecv == 1);
@@ -1525,19 +1522,19 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
-      js_check(isolate.execute("check3.js", "assert(nrecv == 2)"));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
+      js_check(runtime.execute("check3.js", "assert(nrecv == 2)"));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
       // We are idle, so the next poll should be the last.
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
     });
   }
 
   #[test]
   fn test_poll_async_optional_ops() {
     run_in_task(|cx| {
-      let (mut isolate, dispatch_count) = setup(Mode::AsyncUnref);
-      js_check(isolate.execute(
+      let (mut runtime, dispatch_count) = setup(Mode::AsyncUnref);
+      js_check(runtime.execute(
         "check1.js",
         r#"
           Deno.core.setAsyncHandler(1, (buf) => {
@@ -1549,9 +1546,9 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      // The above op never finish, but isolate can finish
+      // The above op never finish, but runtime can finish
       // because the op is an unreffed async op.
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
     })
   }
 
@@ -1604,10 +1601,10 @@ pub mod tests {
   fn dangling_shared_isolate() {
     let v8_isolate_handle = {
       // isolate is dropped at the end of this block
-      let (mut isolate, _dispatch_count) = setup(Mode::Async);
+      let (mut runtime, _dispatch_count) = setup(Mode::Async);
       // TODO(piscisaureus): in rusty_v8, the `thread_safe_handle()` method
       // should not require a mutable reference to `struct rusty_v8::Isolate`.
-      isolate.v8_isolate.as_mut().unwrap().thread_safe_handle()
+      runtime.v8_isolate.as_mut().unwrap().thread_safe_handle()
     };
 
     // this should not SEGFAULT
@@ -1616,8 +1613,8 @@ pub mod tests {
 
   #[test]
   fn overflow_req_sync() {
-    let (mut isolate, dispatch_count) = setup(Mode::OverflowReqSync);
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::OverflowReqSync);
+    js_check(runtime.execute(
       "overflow_req_sync.js",
       r#"
         let asyncRecv = 0;
@@ -1638,8 +1635,8 @@ pub mod tests {
   fn overflow_res_sync() {
     // TODO(ry) This test is quite slow due to memcpy-ing 100MB into JS. We
     // should optimize this.
-    let (mut isolate, dispatch_count) = setup(Mode::OverflowResSync);
-    js_check(isolate.execute(
+    let (mut runtime, dispatch_count) = setup(Mode::OverflowResSync);
+    js_check(runtime.execute(
       "overflow_res_sync.js",
       r#"
         let asyncRecv = 0;
@@ -1659,8 +1656,8 @@ pub mod tests {
   #[test]
   fn overflow_req_async() {
     run_in_task(|cx| {
-      let (mut isolate, dispatch_count) = setup(Mode::OverflowReqAsync);
-      js_check(isolate.execute(
+      let (mut runtime, dispatch_count) = setup(Mode::OverflowReqAsync);
+      js_check(runtime.execute(
         "overflow_req_async.js",
         r#"
          let asyncRecv = 0;
@@ -1678,8 +1675,8 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
-      js_check(isolate.execute("check.js", "assert(asyncRecv == 1);"));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
+      js_check(runtime.execute("check.js", "assert(asyncRecv == 1);"));
     });
   }
 
@@ -1688,8 +1685,8 @@ pub mod tests {
     run_in_task(|_cx| {
       // TODO(ry) This test is quite slow due to memcpy-ing 100MB into JS. We
       // should optimize this.
-      let (mut isolate, dispatch_count) = setup(Mode::OverflowResAsync);
-      js_check(isolate.execute(
+      let (mut runtime, dispatch_count) = setup(Mode::OverflowResAsync);
+      js_check(runtime.execute(
         "overflow_res_async.js",
         r#"
          let asyncRecv = 0;
@@ -1706,8 +1703,8 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      poll_until_ready(&mut isolate, 3).unwrap();
-      js_check(isolate.execute("check.js", "assert(asyncRecv == 1);"));
+      poll_until_ready(&mut runtime, 3).unwrap();
+      js_check(runtime.execute("check.js", "assert(asyncRecv == 1);"));
     });
   }
 
@@ -1716,8 +1713,8 @@ pub mod tests {
     // TODO(ry) This test is quite slow due to memcpy-ing 100MB into JS. We
     // should optimize this.
     run_in_task(|_cx| {
-      let (mut isolate, dispatch_count) = setup(Mode::OverflowResAsync);
-      js_check(isolate.execute(
+      let (mut runtime, dispatch_count) = setup(Mode::OverflowResAsync);
+      js_check(runtime.execute(
         "overflow_res_multiple_dispatch_async.js",
         r#"
          let asyncRecv = 0;
@@ -1737,16 +1734,16 @@ pub mod tests {
          "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      poll_until_ready(&mut isolate, 3).unwrap();
-      js_check(isolate.execute("check.js", "assert(asyncRecv == 2);"));
+      poll_until_ready(&mut runtime, 3).unwrap();
+      js_check(runtime.execute("check.js", "assert(asyncRecv == 2);"));
     });
   }
 
   #[test]
   fn test_pre_dispatch() {
     run_in_task(|mut cx| {
-      let (mut isolate, _dispatch_count) = setup(Mode::OverflowResAsync);
-      js_check(isolate.execute(
+      let (mut runtime, _dispatch_count) = setup(Mode::OverflowResAsync);
+      js_check(runtime.execute(
         "bad_op_id.js",
         r#"
           let thrown;
@@ -1758,7 +1755,7 @@ pub mod tests {
           assert(String(thrown) === "TypeError: Unknown op id: 100");
          "#,
       ));
-      if let Poll::Ready(Err(_)) = isolate.poll_unpin(&mut cx) {
+      if let Poll::Ready(Err(_)) = runtime.poll_unpin(&mut cx) {
         unreachable!();
       }
     });
@@ -1767,9 +1764,9 @@ pub mod tests {
   #[test]
   fn core_test_js() {
     run_in_task(|mut cx| {
-      let (mut isolate, _dispatch_count) = setup(Mode::Async);
-      js_check(isolate.execute("core_test.js", include_str!("core_test.js")));
-      if let Poll::Ready(Err(_)) = isolate.poll_unpin(&mut cx) {
+      let (mut runtime, _dispatch_count) = setup(Mode::Async);
+      js_check(runtime.execute("core_test.js", include_str!("core_test.js")));
+      if let Poll::Ready(Err(_)) = runtime.poll_unpin(&mut cx) {
         unreachable!();
       }
     });
@@ -1777,24 +1774,24 @@ pub mod tests {
 
   #[test]
   fn syntax_error() {
-    let mut isolate =
-      CoreIsolate::new(BasicState::new(), StartupData::None, false);
+    let mut runtime =
+      JsRuntime::new(BasicState::new(), StartupData::None, false);
     let src = "hocuspocus(";
-    let r = isolate.execute("i.js", src);
+    let r = runtime.execute("i.js", src);
     let e = r.unwrap_err();
-    let js_error = e.downcast::<JSError>().unwrap();
+    let js_error = e.downcast::<JsError>().unwrap();
     assert_eq!(js_error.end_column, Some(11));
   }
 
   #[test]
   fn test_encode_decode() {
     run_in_task(|mut cx| {
-      let (mut isolate, _dispatch_count) = setup(Mode::Async);
-      js_check(isolate.execute(
+      let (mut runtime, _dispatch_count) = setup(Mode::Async);
+      js_check(runtime.execute(
         "encode_decode_test.js",
         include_str!("encode_decode_test.js"),
       ));
-      if let Poll::Ready(Err(_)) = isolate.poll_unpin(&mut cx) {
+      if let Poll::Ready(Err(_)) = runtime.poll_unpin(&mut cx) {
         unreachable!();
       }
     });
@@ -1803,30 +1800,30 @@ pub mod tests {
   #[test]
   fn will_snapshot() {
     let snapshot = {
-      let mut isolate =
-        CoreIsolate::new(BasicState::new(), StartupData::None, true);
-      js_check(isolate.execute("a.js", "a = 1 + 2"));
-      isolate.snapshot()
+      let mut runtime =
+        JsRuntime::new(BasicState::new(), StartupData::None, true);
+      js_check(runtime.execute("a.js", "a = 1 + 2"));
+      runtime.snapshot()
     };
 
     let startup_data = StartupData::Snapshot(Snapshot::JustCreated(snapshot));
-    let mut isolate2 = CoreIsolate::new(BasicState::new(), startup_data, false);
-    js_check(isolate2.execute("check.js", "if (a != 3) throw Error('x')"));
+    let mut runtime2 = JsRuntime::new(BasicState::new(), startup_data, false);
+    js_check(runtime2.execute("check.js", "if (a != 3) throw Error('x')"));
   }
 
   #[test]
   fn test_from_boxed_snapshot() {
     let snapshot = {
-      let mut isolate =
-        CoreIsolate::new(BasicState::new(), StartupData::None, true);
-      js_check(isolate.execute("a.js", "a = 1 + 2"));
-      let snap: &[u8] = &*isolate.snapshot();
+      let mut runtime =
+        JsRuntime::new(BasicState::new(), StartupData::None, true);
+      js_check(runtime.execute("a.js", "a = 1 + 2"));
+      let snap: &[u8] = &*runtime.snapshot();
       Vec::from(snap).into_boxed_slice()
     };
 
     let startup_data = StartupData::Snapshot(Snapshot::Boxed(snapshot));
-    let mut isolate2 = CoreIsolate::new(BasicState::new(), startup_data, false);
-    js_check(isolate2.execute("check.js", "if (a != 3) throw Error('x')"));
+    let mut runtime2 = JsRuntime::new(BasicState::new(), startup_data, false);
+    js_check(runtime2.execute("check.js", "if (a != 3) throw Error('x')"));
   }
 
   #[test]
@@ -1835,24 +1832,24 @@ pub mod tests {
       initial: 0,
       max: 20 * 1024, // 20 kB
     };
-    let mut isolate = CoreIsolate::with_heap_limits(
+    let mut runtime = JsRuntime::with_heap_limits(
       BasicState::new(),
       StartupData::None,
       heap_limits,
     );
-    let cb_handle = isolate.thread_safe_handle();
+    let cb_handle = runtime.thread_safe_handle();
 
     let callback_invoke_count = Rc::new(AtomicUsize::default());
     let inner_invoke_count = Rc::clone(&callback_invoke_count);
 
-    isolate.add_near_heap_limit_callback(
+    runtime.add_near_heap_limit_callback(
       move |current_limit, _initial_limit| {
         inner_invoke_count.fetch_add(1, Ordering::SeqCst);
         cb_handle.terminate_execution();
         current_limit * 2
       },
     );
-    let err = isolate
+    let err = runtime
       .execute(
         "script name",
         r#"let s = ""; while(true) { s += "Hello"; }"#,
@@ -1860,21 +1857,21 @@ pub mod tests {
       .expect_err("script should fail");
     assert_eq!(
       "Uncaught Error: execution terminated",
-      err.downcast::<JSError>().unwrap().message
+      err.downcast::<JsError>().unwrap().message
     );
     assert!(callback_invoke_count.load(Ordering::SeqCst) > 0)
   }
 
   #[test]
   fn test_heap_limit_cb_remove() {
-    let mut isolate =
-      CoreIsolate::new(BasicState::new(), StartupData::None, false);
+    let mut runtime =
+      JsRuntime::new(BasicState::new(), StartupData::None, false);
 
-    isolate.add_near_heap_limit_callback(|current_limit, _initial_limit| {
+    runtime.add_near_heap_limit_callback(|current_limit, _initial_limit| {
       current_limit * 2
     });
-    isolate.remove_near_heap_limit_callback(20 * 1024);
-    assert!(isolate.allocations.near_heap_limit_callback_data.is_none());
+    runtime.remove_near_heap_limit_callback(20 * 1024);
+    assert!(runtime.allocations.near_heap_limit_callback_data.is_none());
   }
 
   #[test]
@@ -1883,16 +1880,16 @@ pub mod tests {
       initial: 0,
       max: 20 * 1024, // 20 kB
     };
-    let mut isolate = CoreIsolate::with_heap_limits(
+    let mut runtime = JsRuntime::with_heap_limits(
       BasicState::new(),
       StartupData::None,
       heap_limits,
     );
-    let cb_handle = isolate.thread_safe_handle();
+    let cb_handle = runtime.thread_safe_handle();
 
     let callback_invoke_count_first = Rc::new(AtomicUsize::default());
     let inner_invoke_count_first = Rc::clone(&callback_invoke_count_first);
-    isolate.add_near_heap_limit_callback(
+    runtime.add_near_heap_limit_callback(
       move |current_limit, _initial_limit| {
         inner_invoke_count_first.fetch_add(1, Ordering::SeqCst);
         current_limit * 2
@@ -1901,7 +1898,7 @@ pub mod tests {
 
     let callback_invoke_count_second = Rc::new(AtomicUsize::default());
     let inner_invoke_count_second = Rc::clone(&callback_invoke_count_second);
-    isolate.add_near_heap_limit_callback(
+    runtime.add_near_heap_limit_callback(
       move |current_limit, _initial_limit| {
         inner_invoke_count_second.fetch_add(1, Ordering::SeqCst);
         cb_handle.terminate_execution();
@@ -1909,7 +1906,7 @@ pub mod tests {
       },
     );
 
-    let err = isolate
+    let err = runtime
       .execute(
         "script name",
         r#"let s = ""; while(true) { s += "Hello"; }"#,
@@ -1917,7 +1914,7 @@ pub mod tests {
       .expect_err("script should fail");
     assert_eq!(
       "Uncaught Error: execution terminated",
-      err.downcast::<JSError>().unwrap().message
+      err.downcast::<JsError>().unwrap().message
     );
     assert_eq!(0, callback_invoke_count_first.load(Ordering::SeqCst));
     assert!(callback_invoke_count_second.load(Ordering::SeqCst) > 0);
@@ -1971,10 +1968,10 @@ pub mod tests {
     };
     state.register_op("test", dispatcher);
 
-    let mut isolate =
-      CoreIsolate::new_with_loader(loader, state, StartupData::None, false);
+    let mut runtime =
+      JsRuntime::new_with_loader(loader, state, StartupData::None, false);
 
-    js_check(isolate.execute(
+    js_check(runtime.execute(
       "setup.js",
       r#"
         function assert(cond) {
@@ -1988,7 +1985,7 @@ pub mod tests {
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
 
     let specifier_a = "file:///a.js".to_string();
-    let mod_a = isolate
+    let mod_a = runtime
       .mod_new(
         true,
         &specifier_a,
@@ -2002,7 +1999,7 @@ pub mod tests {
       .unwrap();
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
 
-    let state_rc = CoreIsolate::state(&isolate);
+    let state_rc = JsRuntime::state(&runtime);
     {
       let state = state_rc.borrow();
       let imports = state.modules.get_children(mod_a);
@@ -2011,7 +2008,7 @@ pub mod tests {
         Some(&vec![ModuleSpecifier::resolve_url("file:///b.js").unwrap()])
       );
     }
-    let mod_b = isolate
+    let mod_b = runtime
       .mod_new(false, "file:///b.js", "export function b() { return 'b' }")
       .unwrap();
     {
@@ -2020,14 +2017,14 @@ pub mod tests {
       assert_eq!(imports.len(), 0);
     }
 
-    js_check(isolate.mod_instantiate(mod_b));
+    js_check(runtime.mod_instantiate(mod_b));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
     assert_eq!(resolve_count.load(Ordering::SeqCst), 1);
 
-    js_check(isolate.mod_instantiate(mod_a));
+    js_check(runtime.mod_instantiate(mod_a));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 0);
 
-    js_check(isolate.mod_evaluate(mod_a));
+    js_check(runtime.mod_evaluate(mod_a));
     assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
   }
 
@@ -2066,14 +2063,14 @@ pub mod tests {
     run_in_task(|cx| {
       let loader = Rc::new(DynImportErrLoader::default());
       let count = loader.count.clone();
-      let mut isolate = CoreIsolate::new_with_loader(
+      let mut runtime = JsRuntime::new_with_loader(
         loader,
         BasicState::new(),
         StartupData::None,
         false,
       );
 
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "file:///dyn_import2.js",
         r#"
         (async () => {
@@ -2084,7 +2081,7 @@ pub mod tests {
 
       assert_eq!(count.load(Ordering::Relaxed), 0);
       // We should get an error here.
-      let result = isolate.poll_unpin(cx);
+      let result = runtime.poll_unpin(cx);
       if let Poll::Ready(Ok(_)) = result {
         unreachable!();
       }
@@ -2148,7 +2145,7 @@ pub mod tests {
       let prepare_load_count = loader.prepare_load_count.clone();
       let resolve_count = loader.resolve_count.clone();
       let load_count = loader.load_count.clone();
-      let mut isolate = CoreIsolate::new_with_loader(
+      let mut runtime = JsRuntime::new_with_loader(
         loader,
         BasicState::new(),
         StartupData::None,
@@ -2156,7 +2153,7 @@ pub mod tests {
       );
 
       // Dynamically import mod_b
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "file:///dyn_import3.js",
         r#"
           (async () => {
@@ -2174,14 +2171,14 @@ pub mod tests {
       ));
 
       // First poll runs `prepare_load` hook.
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Pending));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Pending));
       assert_eq!(prepare_load_count.load(Ordering::Relaxed), 1);
 
       // Second poll actually loads modules into the isolate.
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
       assert_eq!(resolve_count.load(Ordering::Relaxed), 4);
       assert_eq!(load_count.load(Ordering::Relaxed), 2);
-      assert!(matches!(isolate.poll_unpin(cx), Poll::Ready(Ok(_))));
+      assert!(matches!(runtime.poll_unpin(cx), Poll::Ready(Ok(_))));
       assert_eq!(resolve_count.load(Ordering::Relaxed), 4);
       assert_eq!(load_count.load(Ordering::Relaxed), 2);
     })
@@ -2193,13 +2190,13 @@ pub mod tests {
     run_in_task(|cx| {
       let loader = Rc::new(DynImportOkLoader::default());
       let prepare_load_count = loader.prepare_load_count.clone();
-      let mut isolate = CoreIsolate::new_with_loader(
+      let mut runtime = JsRuntime::new_with_loader(
         loader,
         BasicState::new(),
         StartupData::None,
         false,
       );
-      js_check(isolate.execute(
+      js_check(runtime.execute(
         "file:///dyn_import3.js",
         r#"
           (async () => {
@@ -2213,10 +2210,10 @@ pub mod tests {
           "#,
       ));
       // First poll runs `prepare_load` hook.
-      let _ = isolate.poll_unpin(cx);
+      let _ = runtime.poll_unpin(cx);
       assert_eq!(prepare_load_count.load(Ordering::Relaxed), 1);
       // Second poll triggers error
-      let _ = isolate.poll_unpin(cx);
+      let _ = runtime.poll_unpin(cx);
     })
   }
 
@@ -2249,7 +2246,7 @@ pub mod tests {
     }
 
     let loader = std::rc::Rc::new(ModsLoader::default());
-    let mut runtime_isolate = CoreIsolate::new_with_loader(
+    let mut runtime = JsRuntime::new_with_loader(
       loader,
       BasicState::new(),
       StartupData::None,
@@ -2260,12 +2257,12 @@ pub mod tests {
     let source_code = "Deno.core.print('hello\\n')".to_string();
 
     let module_id = futures::executor::block_on(
-      runtime_isolate.load_module(&specifier, Some(source_code)),
+      runtime.load_module(&specifier, Some(source_code)),
     )
     .unwrap();
 
-    js_check(runtime_isolate.mod_evaluate(module_id));
+    js_check(runtime.mod_evaluate(module_id));
 
-    let _snapshot = runtime_isolate.snapshot();
+    let _snapshot = runtime.snapshot();
   }
 }
diff --git a/op_crates/web/lib.rs b/op_crates/web/lib.rs
index 674eddbb2..a1ad31a61 100644
--- a/op_crates/web/lib.rs
+++ b/op_crates/web/lib.rs
@@ -1,10 +1,10 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
 use deno_core::js_check;
-use deno_core::CoreIsolate;
+use deno_core::JsRuntime;
 use std::path::PathBuf;
 
-pub fn init(isolate: &mut CoreIsolate) {
+pub fn init(isolate: &mut JsRuntime) {
   let files = vec![
     get_path("00_dom_exception.js"),
     get_path("01_event.js"),
@@ -32,7 +32,7 @@ fn get_path(file_name: &str) -> PathBuf {
 mod tests {
   use deno_core::js_check;
   use deno_core::BasicState;
-  use deno_core::CoreIsolate;
+  use deno_core::JsRuntime;
   use deno_core::StartupData;
   use futures::future::lazy;
   use futures::future::FutureExt;
@@ -46,9 +46,9 @@ mod tests {
     futures::executor::block_on(lazy(move |cx| f(cx)));
   }
 
-  fn setup() -> CoreIsolate {
+  fn setup() -> JsRuntime {
     let mut isolate =
-      CoreIsolate::new(BasicState::new(), StartupData::None, false);
+      JsRuntime::new(BasicState::new(), StartupData::None, false);
     crate::init(&mut isolate);
     isolate
   }