4 files changed, 57 insertions, 3 deletions
diff --git a/cli/BUILD.gn b/cli/BUILD.gn
index 7f19f8b95..84ffe6da4 100644
--- a/cli/BUILD.gn
+++ b/cli/BUILD.gn
@@ -83,6 +83,7 @@ ts_sources = [
   "../js/dispatch_minimal.ts",
   "../js/dom_types.ts",
   "../js/dom_util.ts",
+  "../js/error_stack.ts",
   "../js/errors.ts",
   "../js/event.ts",
   "../js/event_target.ts",
diff --git a/cli/msg.fbs b/cli/msg.fbs
index 2ab776ef3..014bfb7e9 100644
--- a/cli/msg.fbs
+++ b/cli/msg.fbs
@@ -1,5 +1,6 @@
 union Any {
   Accept,
+  ApplySourceMap,
   Cache,
   Chdir,
   Chmod,
@@ -257,6 +258,12 @@ table FetchSourceFileRes {
   data: [ubyte];
 }
 
+table ApplySourceMap {
+  filename: string;
+  line: int;
+  column: int;
+}
+
 table Cache {
   extension: string;
   module_id: string;
diff --git a/cli/ops.rs b/cli/ops.rs
index d4bc94f75..227bb03b3 100644
--- a/cli/ops.rs
+++ b/cli/ops.rs
@@ -20,6 +20,8 @@ use crate::resources;
 use crate::resources::table_entries;
 use crate::resources::Resource;
 use crate::signal::kill;
+use crate::source_maps::get_orig_position;
+use crate::source_maps::CachedMaps;
 use crate::startup_data;
 use crate::state::ThreadSafeState;
 use crate::tokio_util;
@@ -46,6 +48,7 @@ use log;
 use rand::{thread_rng, Rng};
 use remove_dir_all::remove_dir_all;
 use std;
+use std::collections::HashMap;
 use std::convert::From;
 use std::fs;
 use std::net::Shutdown;
@@ -194,6 +197,7 @@ pub fn dispatch_all_legacy(
 pub fn op_selector_std(inner_type: msg::Any) -> Option<CliDispatchFn> {
   match inner_type {
     msg::Any::Accept => Some(op_accept),
+    msg::Any::ApplySourceMap => Some(op_apply_source_map),
     msg::Any::Cache => Some(op_cache),
     msg::Any::Chdir => Some(op_chdir),
     msg::Any::Chmod => Some(op_chmod),
@@ -532,6 +536,48 @@ fn op_fetch_source_file(
   Ok(Op::Sync(result_buf))
 }
 
+fn op_apply_source_map(
+  state: &ThreadSafeState,
+  base: &msg::Base<'_>,
+  data: Option<PinnedBuf>,
+) -> CliOpResult {
+  if !base.sync() {
+    return Err(deno_error::no_async_support());
+  }
+  assert!(data.is_none());
+  let inner = base.inner_as_apply_source_map().unwrap();
+  let cmd_id = base.cmd_id();
+  let filename = inner.filename().unwrap();
+  let line = inner.line();
+  let column = inner.column();
+
+  let mut mappings_map: CachedMaps = HashMap::new();
+  let (orig_filename, orig_line, orig_column) = get_orig_position(
+    filename.to_owned(),
+    line.into(),
+    column.into(),
+    &mut mappings_map,
+    &state.ts_compiler,
+  );
+
+  let builder = &mut FlatBufferBuilder::new();
+  let msg_args = msg::ApplySourceMapArgs {
+    filename: Some(builder.create_string(&orig_filename)),
+    line: orig_line as i32,
+    column: orig_column as i32,
+  };
+  let res_inner = msg::ApplySourceMap::create(builder, &msg_args);
+  ok_buf(serialize_response(
+    cmd_id,
+    builder,
+    msg::BaseArgs {
+      inner: Some(res_inner.as_union_value()),
+      inner_type: msg::Any::ApplySourceMap,
+      ..Default::default()
+    },
+  ))
+}
+
 fn op_chdir(
   _state: &ThreadSafeState,
   base: &msg::Base<'_>,
diff --git a/cli/source_maps.rs b/cli/source_maps.rs
index 6b453d883..a886c6afc 100644
--- a/cli/source_maps.rs
+++ b/cli/source_maps.rs
@@ -17,9 +17,9 @@ pub trait SourceMapGetter {
 
 /// Cached filename lookups. The key can be None if a previous lookup failed to
 /// find a SourceMap.
-type CachedMaps = HashMap<String, Option<SourceMap>>;
+pub type CachedMaps = HashMap<String, Option<SourceMap>>;
 
-struct SourceMap {
+pub struct SourceMap {
   mappings: Mappings,
   sources: Vec<String>,
 }
@@ -202,7 +202,7 @@ fn get_maybe_orig_position<G: SourceMapGetter>(
   }
 }
 
-fn get_orig_position<G: SourceMapGetter>(
+pub fn get_orig_position<G: SourceMapGetter>(
   script_name: String,
   line: i64,
   column: i64,