14 files changed, 191 insertions, 240 deletions

diff --git a/cli/build.rs b/cli/build.rs
index f2abb9529..7ed947f4e 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::JsRuntime;
-use deno_core::StartupData;
+use deno_core::RuntimeOptions;
 use std::collections::HashMap;
 use std::env;
 use std::path::Path;
@@ -37,7 +37,10 @@ fn create_snapshot(
 }
 
 fn create_runtime_snapshot(snapshot_path: &Path, files: Vec<PathBuf>) {
-  let isolate = JsRuntime::new(StartupData::None, true);
+  let isolate = JsRuntime::new(RuntimeOptions {
+    will_snapshot: true,
+    ..Default::default()
+  });
   create_snapshot(isolate, snapshot_path, files);
 }
 
@@ -70,7 +73,10 @@ fn create_compiler_snapshot(
     cwd.join("dts/lib.deno.unstable.d.ts"),
   );
 
-  let mut isolate = JsRuntime::new(StartupData::None, true);
+  let mut isolate = JsRuntime::new(RuntimeOptions {
+    will_snapshot: true,
+    ..Default::default()
+  });
   isolate.register_op(
     "op_fetch_asset",
     op_fetch_asset::op_fetch_asset(custom_libs),
diff --git a/cli/js.rs b/cli/js.rs
index 2dc56710d..1c738af76 100644
--- a/cli/js.rs
+++ b/cli/js.rs
@@ -1,3 +1,7 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::Snapshot;
+
 pub const TS_VERSION: &str = env!("TS_VERSION");
 
 pub static CLI_SNAPSHOT: &[u8] =
@@ -11,12 +15,24 @@ pub static SHARED_GLOBALS_LIB: &str =
 pub static WINDOW_LIB: &str = include_str!("dts/lib.deno.window.d.ts");
 pub static UNSTABLE_NS_LIB: &str = include_str!("dts/lib.deno.unstable.d.ts");
 
+pub fn deno_isolate_init() -> Snapshot {
+  debug!("Deno isolate init with snapshots.");
+  let data = CLI_SNAPSHOT;
+  Snapshot::Static(data)
+}
+
+pub fn compiler_isolate_init() -> Snapshot {
+  debug!("Deno compiler isolate init with snapshots.");
+  let data = COMPILER_SNAPSHOT;
+  Snapshot::Static(data)
+}
+
 #[test]
 fn cli_snapshot() {
-  let mut isolate = deno_core::JsRuntime::new(
-    deno_core::StartupData::Snapshot(deno_core::Snapshot::Static(CLI_SNAPSHOT)),
-    false,
-  );
+  let mut isolate = deno_core::JsRuntime::new(deno_core::RuntimeOptions {
+    startup_snapshot: Some(deno_isolate_init()),
+    ..Default::default()
+  });
   deno_core::js_check(isolate.execute(
     "<anon>",
     r#"
@@ -30,12 +46,10 @@ fn cli_snapshot() {
 
 #[test]
 fn compiler_snapshot() {
-  let mut isolate = deno_core::JsRuntime::new(
-    deno_core::StartupData::Snapshot(deno_core::Snapshot::Static(
-      COMPILER_SNAPSHOT,
-    )),
-    false,
-  );
+  let mut isolate = deno_core::JsRuntime::new(deno_core::RuntimeOptions {
+    startup_snapshot: Some(compiler_isolate_init()),
+    ..Default::default()
+  });
   deno_core::js_check(isolate.execute(
     "<anon>",
     r#"
diff --git a/cli/main.rs b/cli/main.rs
index d5329eeb4..39c931349 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -56,7 +56,6 @@ mod repl;
 pub mod resolve_addr;
 pub mod signal;
 pub mod source_maps;
-mod startup_data;
 pub mod state;
 mod swc_util;
 mod test_runner;
diff --git a/cli/ops/worker_host.rs b/cli/ops/worker_host.rs
index 158865abc..6a100b198 100644
--- a/cli/ops/worker_host.rs
+++ b/cli/ops/worker_host.rs
@@ -4,7 +4,6 @@ use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::ops::io::get_stdio;
 use crate::permissions::Permissions;
-use crate::startup_data;
 use crate::tokio_util::create_basic_runtime;
 use crate::web_worker::WebWorker;
 use crate::web_worker::WebWorkerHandle;
@@ -48,12 +47,7 @@ fn create_web_worker(
     specifier,
   )?;
 
-  let mut worker = WebWorker::new(
-    name.clone(),
-    startup_data::deno_isolate_init(),
-    &cli_state,
-    has_deno_namespace,
-  );
+  let mut worker = WebWorker::new(name.clone(), &cli_state, has_deno_namespace);
 
   if has_deno_namespace {
     let state = worker.isolate.op_state();
diff --git a/cli/startup_data.rs b/cli/startup_data.rs
deleted file mode 100644
index 1cdfb4188..000000000
--- a/cli/startup_data.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-
-use crate::js::CLI_SNAPSHOT;
-use crate::js::COMPILER_SNAPSHOT;
-use deno_core::Snapshot;
-use deno_core::StartupData;
-
-pub fn deno_isolate_init() -> StartupData<'static> {
-  debug!("Deno isolate init with snapshots.");
-  let data = CLI_SNAPSHOT;
-  StartupData::Snapshot(Snapshot::Static(data))
-}
-
-pub fn compiler_isolate_init() -> StartupData<'static> {
-  debug!("Deno isolate init with snapshots.");
-  let data = COMPILER_SNAPSHOT;
-  StartupData::Snapshot(Snapshot::Static(data))
-}
diff --git a/cli/tsc.rs b/cli/tsc.rs
index 77b855dd1..e3c7d9d84 100644
--- a/cli/tsc.rs
+++ b/cli/tsc.rs
@@ -9,6 +9,7 @@ use crate::file_fetcher::SourceFileFetcher;
 use crate::flags::Flags;
 use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
+use crate::js;
 use crate::module_graph::ModuleGraph;
 use crate::module_graph::ModuleGraphLoader;
 use crate::msg;
@@ -16,7 +17,6 @@ use crate::msg::MediaType;
 use crate::ops;
 use crate::permissions::Permissions;
 use crate::source_maps::SourceMapGetter;
-use crate::startup_data;
 use crate::state::State;
 use crate::swc_util;
 use crate::swc_util::AstParser;
@@ -28,7 +28,6 @@ use crate::worker::Worker;
 use core::task::Context;
 use deno_core::ErrBox;
 use deno_core::ModuleSpecifier;
-use deno_core::StartupData;
 use futures::future::Future;
 use futures::future::FutureExt;
 use log::debug;
@@ -134,12 +133,9 @@ pub struct CompilerWorker {
 }
 
 impl CompilerWorker {
-  pub fn new(
-    name: String,
-    startup_data: StartupData,
-    state: &Rc<State>,
-  ) -> Self {
-    let mut worker = Worker::new(name, startup_data, state);
+  pub fn new(name: String, state: &Rc<State>) -> Self {
+    let mut worker =
+      Worker::new(name, Some(js::compiler_isolate_init()), state);
     let response = Arc::new(Mutex::new(None));
     ops::runtime::init(&mut worker);
     ops::errors::init(&mut worker);
@@ -232,11 +228,7 @@ fn create_compiler_worker(
   // Count how many times we start the compiler worker.
   global_state.compiler_starts.fetch_add(1, Ordering::SeqCst);
 
-  let mut worker = CompilerWorker::new(
-    "TS".to_string(),
-    startup_data::compiler_isolate_init(),
-    &worker_state,
-  );
+  let mut worker = CompilerWorker::new("TS".to_string(), &worker_state);
   worker
     .execute("globalThis.bootstrapCompilerRuntime()")
     .unwrap();
diff --git a/cli/web_worker.rs b/cli/web_worker.rs
index ebf8fa698..b0990d313 100644
--- a/cli/web_worker.rs
+++ b/cli/web_worker.rs
@@ -1,5 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
+use crate::js;
 use crate::ops;
 use crate::state::State;
 use crate::worker::Worker;
@@ -7,7 +8,6 @@ use crate::worker::WorkerEvent;
 use crate::worker::WorkerHandle;
 use deno_core::v8;
 use deno_core::ErrBox;
-use deno_core::StartupData;
 use futures::channel::mpsc;
 use futures::future::FutureExt;
 use futures::stream::StreamExt;
@@ -85,11 +85,10 @@ pub struct WebWorker {
 impl WebWorker {
   pub fn new(
     name: String,
-    startup_data: StartupData,
     state: &Rc<State>,
     has_deno_namespace: bool,
   ) -> Self {
-    let mut worker = Worker::new(name, startup_data, &state);
+    let mut worker = Worker::new(name, Some(js::deno_isolate_init()), &state);
 
     let terminated = Arc::new(AtomicBool::new(false));
     let isolate_handle = worker.isolate.thread_safe_handle();
@@ -240,19 +239,13 @@ impl Future for WebWorker {
 #[cfg(test)]
 mod tests {
   use super::*;
-  use crate::startup_data;
   use crate::state::State;
   use crate::tokio_util;
   use crate::worker::WorkerEvent;
 
   fn create_test_worker() -> WebWorker {
     let state = State::mock("./hello.js");
-    let mut worker = WebWorker::new(
-      "TEST".to_string(),
-      startup_data::deno_isolate_init(),
-      &state,
-      false,
-    );
+    let mut worker = WebWorker::new("TEST".to_string(), &state, false);
     worker
       .execute("bootstrap.workerRuntime(\"TEST\", false)")
       .unwrap();
diff --git a/cli/worker.rs b/cli/worker.rs
index baab81ff6..7ebd2a79e 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -3,15 +3,16 @@
 use crate::fmt_errors::JsError;
 use crate::global_state::GlobalState;
 use crate::inspector::DenoInspector;
+use crate::js;
 use crate::ops;
 use crate::ops::io::get_stdio;
-use crate::startup_data;
 use crate::state::State;
 use deno_core::ErrBox;
 use deno_core::JsRuntime;
 use deno_core::ModuleId;
 use deno_core::ModuleSpecifier;
-use deno_core::StartupData;
+use deno_core::RuntimeOptions;
+use deno_core::Snapshot;
 use futures::channel::mpsc;
 use futures::future::FutureExt;
 use futures::stream::StreamExt;
@@ -102,11 +103,14 @@ pub struct Worker {
 impl Worker {
   pub fn new(
     name: String,
-    startup_data: StartupData,
+    startup_snapshot: Option<Snapshot>,
     state: &Rc<State>,
   ) -> Self {
-    let mut isolate =
-      JsRuntime::new_with_loader(state.clone(), startup_data, false);
+    let mut isolate = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(state.clone()),
+      startup_snapshot,
+      ..Default::default()
+    });
     {
       let global_state = state.global_state.clone();
       let js_runtime_state = JsRuntime::state(&isolate);
@@ -257,8 +261,12 @@ pub struct MainWorker(Worker);
 
 impl MainWorker {
   // TODO(ry) combine MainWorker::new and MainWorker::create.
-  fn new(name: String, startup_data: StartupData, state: &Rc<State>) -> Self {
-    let mut worker = Worker::new(name, startup_data, state);
+  fn new(
+    name: String,
+    startup_snapshot: Option<Snapshot>,
+    state: &Rc<State>,
+  ) -> Self {
+    let mut worker = Worker::new(name, startup_snapshot, state);
     {
       ops::runtime::init(&mut worker);
       ops::runtime_compiler::init(&mut worker);
@@ -299,7 +307,7 @@ impl MainWorker {
     )?;
     let mut worker = MainWorker::new(
       "main".to_string(),
-      startup_data::deno_isolate_init(),
+      Some(js::deno_isolate_init()),
       &state,
     );
     {
@@ -340,7 +348,7 @@ mod tests {
   use super::*;
   use crate::flags;
   use crate::global_state::GlobalState;
-  use crate::startup_data;
+  use crate::js;
   use crate::tokio_util;
   use std::sync::atomic::Ordering;
 
@@ -357,8 +365,7 @@ mod tests {
       State::new(&global_state, None, module_specifier.clone(), None, false)
         .unwrap();
     tokio_util::run_basic(async {
-      let mut worker =
-        MainWorker::new("TEST".to_string(), StartupData::None, &state);
+      let mut worker = MainWorker::new("TEST".to_string(), None, &state);
       let result = worker.execute_module(&module_specifier).await;
       if let Err(err) = result {
         eprintln!("execute_mod err {:?}", err);
@@ -385,8 +392,7 @@ mod tests {
       State::new(&global_state, None, module_specifier.clone(), None, false)
         .unwrap();
     tokio_util::run_basic(async {
-      let mut worker =
-        MainWorker::new("TEST".to_string(), StartupData::None, &state);
+      let mut worker = MainWorker::new("TEST".to_string(), None, &state);
       let result = worker.execute_module(&module_specifier).await;
       if let Err(err) = result {
         eprintln!("execute_mod err {:?}", err);
@@ -422,7 +428,7 @@ mod tests {
         .unwrap();
     let mut worker = MainWorker::new(
       "TEST".to_string(),
-      startup_data::deno_isolate_init(),
+      Some(js::deno_isolate_init()),
       &state,
     );
     worker.execute("bootstrap.mainRuntime()").unwrap();
@@ -442,7 +448,7 @@ mod tests {
     let state = State::mock("./hello.js");
     let mut worker = MainWorker::new(
       "TEST".to_string(),
-      startup_data::deno_isolate_init(),
+      Some(js::deno_isolate_init()),
       &state,
     );
     worker.execute("bootstrap.mainRuntime()").unwrap();
diff --git a/core/examples/http_bench_bin_ops.rs b/core/examples/http_bench_bin_ops.rs
index b29af8b9d..2748705ea 100644
--- a/core/examples/http_bench_bin_ops.rs
+++ b/core/examples/http_bench_bin_ops.rs
@@ -6,8 +6,6 @@ use deno_core::BufVec;
 use deno_core::JsRuntime;
 use deno_core::Op;
 use deno_core::OpState;
-use deno_core::Script;
-use deno_core::StartupData;
 use deno_core::ZeroCopyBuf;
 use futures::future::poll_fn;
 use futures::future::FutureExt;
@@ -78,12 +76,7 @@ impl From<Record> for RecordBuf {
 }
 
 fn create_isolate() -> JsRuntime {
-  let startup_data = StartupData::Script(Script {
-    source: include_str!("http_bench_bin_ops.js"),
-    filename: "http_bench_bin_ops.js",
-  });
-
-  let mut isolate = JsRuntime::new(startup_data, false);
+  let mut isolate = JsRuntime::new(Default::default());
   register_op_bin_sync(&mut isolate, "listen", op_listen);
   register_op_bin_sync(&mut isolate, "close", op_close);
   register_op_bin_async(&mut isolate, "accept", op_accept);
@@ -252,13 +245,23 @@ fn main() {
   // NOTE: `--help` arg will display V8 help and exit
   deno_core::v8_set_flags(env::args().collect());
 
-  let isolate = create_isolate();
+  let mut isolate = create_isolate();
   let mut runtime = runtime::Builder::new()
     .basic_scheduler()
     .enable_all()
     .build()
     .unwrap();
-  js_check(runtime.block_on(isolate));
+
+  let future = async move {
+    isolate
+      .execute(
+        "http_bench_bin_ops.js",
+        include_str!("http_bench_bin_ops.js"),
+      )
+      .unwrap();
+    isolate.await
+  };
+  js_check(runtime.block_on(future));
 }
 
 #[test]
diff --git a/core/examples/http_bench_json_ops.rs b/core/examples/http_bench_json_ops.rs
index dc0c837e2..a7db450e4 100644
--- a/core/examples/http_bench_json_ops.rs
+++ b/core/examples/http_bench_json_ops.rs
@@ -6,8 +6,6 @@ use deno_core::BufVec;
 use deno_core::ErrBox;
 use deno_core::JsRuntime;
 use deno_core::OpState;
-use deno_core::Script;
-use deno_core::StartupData;
 use deno_core::ZeroCopyBuf;
 use futures::future::poll_fn;
 use futures::future::Future;
@@ -42,11 +40,7 @@ impl log::Log for Logger {
 }
 
 fn create_isolate() -> JsRuntime {
-  let startup_data = StartupData::Script(Script {
-    source: include_str!("http_bench_json_ops.js"),
-    filename: "http_bench_json_ops.js",
-  });
-  let mut runtime = JsRuntime::new(startup_data, false);
+  let mut runtime = JsRuntime::new(Default::default());
   runtime.register_op("listen", deno_core::json_op_sync(op_listen));
   runtime.register_op("close", deno_core::json_op_sync(op_close));
   runtime.register_op("accept", deno_core::json_op_async(op_accept));
@@ -183,11 +177,21 @@ fn main() {
   // NOTE: `--help` arg will display V8 help and exit
   deno_core::v8_set_flags(env::args().collect());
 
-  let isolate = create_isolate();
+  let mut isolate = create_isolate();
   let mut runtime = runtime::Builder::new()
     .basic_scheduler()
     .enable_all()
     .build()
     .unwrap();
-  js_check(runtime.block_on(isolate));
+
+  let future = async move {
+    isolate
+      .execute(
+        "http_bench_json_ops.js",
+        include_str!("http_bench_json_ops.js"),
+      )
+      .unwrap();
+    isolate.await
+  };
+  js_check(runtime.block_on(future));
 }
diff --git a/core/lib.rs b/core/lib.rs
index 450b7378a..bb54f5133 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -51,9 +51,8 @@ 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::RuntimeOptions;
 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 57068528d..eae2a8d9f 100644
--- a/core/modules.rs
+++ b/core/modules.rs
@@ -442,7 +442,7 @@ mod tests {
   use super::*;
   use crate::js_check;
   use crate::JsRuntime;
-  use crate::StartupData;
+  use crate::RuntimeOptions;
   use futures::future::FutureExt;
   use std::error::Error;
   use std::fmt;
@@ -619,8 +619,10 @@ mod tests {
   fn test_recursive_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, false);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      ..Default::default()
+    });
     let spec = ModuleSpecifier::resolve_url("file:///a.js").unwrap();
     let a_id_fut = runtime.load_module(&spec, None);
     let a_id = futures::executor::block_on(a_id_fut).expect("Failed to load");
@@ -682,8 +684,10 @@ mod tests {
   fn test_circular_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, false);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      ..Default::default()
+    });
 
     let fut = async move {
       let spec = ModuleSpecifier::resolve_url("file:///circular1.js").unwrap();
@@ -756,8 +760,10 @@ mod tests {
   fn test_redirect_load() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, false);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      ..Default::default()
+    });
 
     let fut = async move {
       let spec = ModuleSpecifier::resolve_url("file:///redirect1.js").unwrap();
@@ -821,8 +827,10 @@ mod tests {
     run_in_task(|mut cx| {
       let loader = MockLoader::new();
       let loads = loader.loads.clone();
-      let mut runtime =
-        JsRuntime::new_with_loader(loader, StartupData::None, false);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        module_loader: Some(loader),
+        ..Default::default()
+      });
       let spec = ModuleSpecifier::resolve_url("file:///main.js").unwrap();
       let mut recursive_load = runtime.load_module(&spec, None).boxed_local();
 
@@ -867,8 +875,10 @@ mod tests {
   fn loader_disappears_after_error() {
     run_in_task(|mut cx| {
       let loader = MockLoader::new();
-      let mut runtime =
-        JsRuntime::new_with_loader(loader, StartupData::None, false);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        module_loader: Some(loader),
+        ..Default::default()
+      });
       let spec = ModuleSpecifier::resolve_url("file:///bad_import.js").unwrap();
       let mut load_fut = runtime.load_module(&spec, None).boxed_local();
       let result = load_fut.poll_unpin(&mut cx);
@@ -896,8 +906,10 @@ mod tests {
   fn recursive_load_main_with_code() {
     let loader = MockLoader::new();
     let loads = loader.loads.clone();
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, false);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      ..Default::default()
+    });
     // In default resolution code should be empty.
     // Instead we explicitly pass in our own code.
     // The behavior should be very similar to /a.js.
diff --git a/core/runtime.rs b/core/runtime.rs
index e6fc23084..045613224 100644
--- a/core/runtime.rs
+++ b/core/runtime.rs
@@ -32,7 +32,6 @@ use std::any::Any;
 use std::cell::Cell;
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::convert::From;
 use std::convert::TryFrom;
 use std::ffi::c_void;
 use std::mem::forget;
@@ -47,52 +46,12 @@ use std::task::Poll;
 
 type PendingOpFuture = Pin<Box<dyn Future<Output = (OpId, Box<[u8]>)>>>;
 
-/// Stores a script used to initialize a Isolate
-pub struct Script<'a> {
-  pub source: &'a str,
-  pub filename: &'a str,
-}
-
-// TODO(ry) It's ugly that we have both Script and OwnedScript. Ideally we
-// wouldn't expose such twiddly complexity.
-struct OwnedScript {
-  pub source: String,
-  pub filename: String,
-}
-
-impl From<Script<'_>> for OwnedScript {
-  fn from(s: Script) -> OwnedScript {
-    OwnedScript {
-      source: s.source.to_string(),
-      filename: s.filename.to_string(),
-    }
-  }
-}
-
 pub enum Snapshot {
   Static(&'static [u8]),
   JustCreated(v8::StartupData),
   Boxed(Box<[u8]>),
 }
 
-/// Represents data used to initialize an isolate at startup, either
-/// in the form of a binary snapshot or a JavaScript source file.
-pub enum StartupData<'a> {
-  Script(Script<'a>),
-  Snapshot(Snapshot),
-  None,
-}
-
-impl StartupData<'_> {
-  fn into_options(self) -> (Option<OwnedScript>, Option<Snapshot>) {
-    match self {
-      Self::Script(script) => (Some(script.into()), None),
-      Self::Snapshot(snapshot) => (None, Some(snapshot)),
-      Self::None => (None, None),
-    }
-  }
-}
-
 type JsErrorCreateFn = dyn Fn(JsError) -> ErrBox;
 
 pub type GetErrorClassFn = &'static dyn for<'e> Fn(&'e ErrBox) -> &'static str;
@@ -121,7 +80,6 @@ pub struct JsRuntime {
   snapshot_creator: Option<v8::SnapshotCreator>,
   has_snapshotted: bool,
   needs_init: bool,
-  startup_script: Option<OwnedScript>,
   allocations: IsolateAllocations,
 }
 
@@ -219,48 +177,24 @@ pub struct HeapLimits {
   pub max: usize,
 }
 
-pub(crate) struct IsolateOptions {
-  loader: Rc<dyn ModuleLoader>,
-  startup_script: Option<OwnedScript>,
-  startup_snapshot: Option<Snapshot>,
-  will_snapshot: bool,
-  heap_limits: Option<HeapLimits>,
-}
-
-impl JsRuntime {
-  /// startup_data defines the snapshot or script used at startup to initialize
-  /// the isolate.
-  pub fn new(startup_data: StartupData, will_snapshot: bool) -> Self {
-    let (startup_script, startup_snapshot) = startup_data.into_options();
-    let options = IsolateOptions {
-      loader: Rc::new(NoopModuleLoader),
-      startup_script,
-      startup_snapshot,
-      will_snapshot,
-      heap_limits: None,
-    };
-
-    Self::from_options(options)
-  }
+#[derive(Default)]
+pub struct RuntimeOptions {
+  /// Implementation of `ModuleLoader` which will be
+  /// called when V8 requests to load ES modules.
+  ///
+  /// If not provided runtime will error if code being
+  /// executed tries to load modules.
+  pub module_loader: Option<Rc<dyn ModuleLoader>>,
 
-  // TODO(bartlomieju): add `new_with_loader_and_heap_limits` function?
-  /// Create new isolate that can load and execute ESModules.
-  pub fn new_with_loader(
-    loader: Rc<dyn ModuleLoader>,
-    startup_data: StartupData,
-    will_snapshot: bool,
-  ) -> Self {
-    let (startup_script, startup_snapshot) = startup_data.into_options();
-    let options = IsolateOptions {
-      loader,
-      startup_script,
-      startup_snapshot,
-      will_snapshot,
-      heap_limits: None,
-    };
+  /// V8 snapshot that should be loaded on startup.
+  ///
+  /// Currently can't be used with `will_snapshot`.
+  pub startup_snapshot: Option<Snapshot>,
 
-    Self::from_options(options)
-  }
+  /// Prepare runtime to take snapshot of loaded code.
+  ///
+  /// Currently can't be used with `startup_snapshot`.
+  pub will_snapshot: bool,
 
   /// This is useful for controlling memory usage of scripts.
   ///
@@ -268,23 +202,11 @@ impl JsRuntime {
   ///
   /// Make sure to use [`add_near_heap_limit_callback`](#method.add_near_heap_limit_callback)
   /// to prevent v8 from crashing when reaching the upper limit.
-  pub fn with_heap_limits(
-    startup_data: StartupData,
-    heap_limits: HeapLimits,
-  ) -> Self {
-    let (startup_script, startup_snapshot) = startup_data.into_options();
-    let options = IsolateOptions {
-      loader: Rc::new(NoopModuleLoader),
-      startup_script,
-      startup_snapshot,
-      will_snapshot: false,
-      heap_limits: Some(heap_limits),
-    };
-
-    Self::from_options(options)
-  }
+  pub heap_limits: Option<HeapLimits>,
+}
 
-  fn from_options(options: IsolateOptions) -> Self {
+impl JsRuntime {
+  pub fn new(options: RuntimeOptions) -> Self {
     static DENO_INIT: Once = Once::new();
     DENO_INIT.call_once(|| {
       unsafe { v8_init() };
@@ -339,6 +261,10 @@ impl JsRuntime {
       (isolate, None)
     };
 
+    let loader = options
+      .module_loader
+      .unwrap_or_else(|| Rc::new(NoopModuleLoader));
+
     let op_state = OpState::default();
 
     isolate.set_slot(Rc::new(RefCell::new(JsRuntimeState {
@@ -354,7 +280,7 @@ impl JsRuntime {
       op_state: Rc::new(RefCell::new(op_state)),
       have_unpolled_ops: Cell::new(false),
       modules: Modules::new(),
-      loader: options.loader,
+      loader,
       dyn_import_map: HashMap::new(),
       preparing_dyn_imports: FuturesUnordered::new(),
       pending_dyn_imports: FuturesUnordered::new(),
@@ -366,7 +292,6 @@ impl JsRuntime {
       snapshot_creator: maybe_snapshot_creator,
       has_snapshotted: false,
       needs_init: true,
-      startup_script: options.startup_script,
       allocations: IsolateAllocations::default(),
     }
   }
@@ -393,10 +318,6 @@ impl JsRuntime {
     if self.needs_init {
       self.needs_init = false;
       js_check(self.execute("core.js", include_str!("core.js")));
-      // Maybe execute the startup script.
-      if let Some(s) = self.startup_script.take() {
-        self.execute(&s.filename, &s.source).unwrap()
-      }
     }
   }
 
@@ -1413,7 +1334,7 @@ pub mod tests {
 
   fn setup(mode: Mode) -> (JsRuntime, Arc<AtomicUsize>) {
     let dispatch_count = Arc::new(AtomicUsize::new(0));
-    let mut runtime = JsRuntime::new(StartupData::None, false);
+    let mut runtime = JsRuntime::new(Default::default());
     let op_state = runtime.op_state();
     op_state.borrow_mut().put(TestState {
       mode,
@@ -1784,7 +1705,7 @@ pub mod tests {
 
   #[test]
   fn syntax_error() {
-    let mut runtime = JsRuntime::new(StartupData::None, false);
+    let mut runtime = JsRuntime::new(Default::default());
     let src = "hocuspocus(";
     let r = runtime.execute("i.js", src);
     let e = r.unwrap_err();
@@ -1809,27 +1730,39 @@ pub mod tests {
   #[test]
   fn will_snapshot() {
     let snapshot = {
-      let mut runtime = JsRuntime::new(StartupData::None, true);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        will_snapshot: true,
+        ..Default::default()
+      });
       js_check(runtime.execute("a.js", "a = 1 + 2"));
       runtime.snapshot()
     };
 
-    let startup_data = StartupData::Snapshot(Snapshot::JustCreated(snapshot));
-    let mut runtime2 = JsRuntime::new(startup_data, false);
+    let snapshot = Snapshot::JustCreated(snapshot);
+    let mut runtime2 = JsRuntime::new(RuntimeOptions {
+      startup_snapshot: Some(snapshot),
+      ..Default::default()
+    });
     js_check(runtime2.execute("check.js", "if (a != 3) throw Error('x')"));
   }
 
   #[test]
   fn test_from_boxed_snapshot() {
     let snapshot = {
-      let mut runtime = JsRuntime::new(StartupData::None, true);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        will_snapshot: true,
+        ..Default::default()
+      });
       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 runtime2 = JsRuntime::new(startup_data, false);
+    let snapshot = Snapshot::Boxed(snapshot);
+    let mut runtime2 = JsRuntime::new(RuntimeOptions {
+      startup_snapshot: Some(snapshot),
+      ..Default::default()
+    });
     js_check(runtime2.execute("check.js", "if (a != 3) throw Error('x')"));
   }
 
@@ -1839,8 +1772,10 @@ pub mod tests {
       initial: 0,
       max: 20 * 1024, // 20 kB
     };
-    let mut runtime =
-      JsRuntime::with_heap_limits(StartupData::None, heap_limits);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      heap_limits: Some(heap_limits),
+      ..Default::default()
+    });
     let cb_handle = runtime.thread_safe_handle();
 
     let callback_invoke_count = Rc::new(AtomicUsize::default());
@@ -1868,7 +1803,7 @@ pub mod tests {
 
   #[test]
   fn test_heap_limit_cb_remove() {
-    let mut runtime = JsRuntime::new(StartupData::None, false);
+    let mut runtime = JsRuntime::new(Default::default());
 
     runtime.add_near_heap_limit_callback(|current_limit, _initial_limit| {
       current_limit * 2
@@ -1883,8 +1818,10 @@ pub mod tests {
       initial: 0,
       max: 20 * 1024, // 20 kB
     };
-    let mut runtime =
-      JsRuntime::with_heap_limits(StartupData::None, heap_limits);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      heap_limits: Some(heap_limits),
+      ..Default::default()
+    });
     let cb_handle = runtime.thread_safe_handle();
 
     let callback_invoke_count_first = Rc::new(AtomicUsize::default());
@@ -1966,8 +1903,10 @@ pub mod tests {
       Op::Async(futures::future::ready(buf).boxed())
     };
 
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, false);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      ..Default::default()
+    });
     runtime.register_op("test", dispatcher);
 
     js_check(runtime.execute(
@@ -2062,8 +2001,10 @@ pub mod tests {
     run_in_task(|cx| {
       let loader = Rc::new(DynImportErrLoader::default());
       let count = loader.count.clone();
-      let mut runtime =
-        JsRuntime::new_with_loader(loader, StartupData::None, false);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        module_loader: Some(loader),
+        ..Default::default()
+      });
 
       js_check(runtime.execute(
         "file:///dyn_import2.js",
@@ -2140,8 +2081,10 @@ 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 runtime =
-        JsRuntime::new_with_loader(loader, StartupData::None, false);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        module_loader: Some(loader),
+        ..Default::default()
+      });
 
       // Dynamically import mod_b
       js_check(runtime.execute(
@@ -2181,8 +2124,10 @@ pub mod tests {
     run_in_task(|cx| {
       let loader = Rc::new(DynImportOkLoader::default());
       let prepare_load_count = loader.prepare_load_count.clone();
-      let mut runtime =
-        JsRuntime::new_with_loader(loader, StartupData::None, false);
+      let mut runtime = JsRuntime::new(RuntimeOptions {
+        module_loader: Some(loader),
+        ..Default::default()
+      });
       js_check(runtime.execute(
         "file:///dyn_import3.js",
         r#"
@@ -2233,8 +2178,11 @@ pub mod tests {
     }
 
     let loader = std::rc::Rc::new(ModsLoader::default());
-    let mut runtime =
-      JsRuntime::new_with_loader(loader, StartupData::None, true);
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      module_loader: Some(loader),
+      will_snapshot: true,
+      ..Default::default()
+    });
 
     let specifier = ModuleSpecifier::resolve_url("file:///main.js").unwrap();
     let source_code = "Deno.core.print('hello\\n')".to_string();
diff --git a/op_crates/web/lib.rs b/op_crates/web/lib.rs
index 03107524a..96f269a1d 100644
--- a/op_crates/web/lib.rs
+++ b/op_crates/web/lib.rs
@@ -34,7 +34,6 @@ pub fn get_declaration() -> PathBuf {
 mod tests {
   use deno_core::js_check;
   use deno_core::JsRuntime;
-  use deno_core::StartupData;
   use futures::future::lazy;
   use futures::future::FutureExt;
   use futures::task::Context;
@@ -48,7 +47,7 @@ mod tests {
   }
 
   fn setup() -> JsRuntime {
-    let mut isolate = JsRuntime::new(StartupData::None, false);
+    let mut isolate = JsRuntime::new(Default::default());
     crate::init(&mut isolate);
     isolate
   }