diff --git a/test/src/jest-config.ts b/test/src/jest-config.ts
index d99100a..9af9403 100644
--- a/test/src/jest-config.ts
+++ b/test/src/jest-config.ts
@@ -1,5 +1,6 @@
 export function jestConfig() {
   return {
+    moduleFileExtensions: ["js", "json"],
     modulePathIgnorePatterns: [`${process.env.JEST_ROOT}/bazel/`],
     testPathIgnorePatterns: [`${process.env.JEST_ROOT}/bazel/`],
     testTimeout: 60 * 1000,
diff --git a/ts-proto/rules.bzl b/ts-proto/rules.bzl
index 97ee9a2..be44b35 100644
--- a/ts-proto/rules.bzl
+++ b/ts-proto/rules.bzl
@@ -189,6 +189,10 @@ def _ts_proto_libraries_impl(ctx):
                 js.append(map)
                 js_outputs.append(map)
 
+                # Include .ts file with source map. Used by VSCode debugger as
+                # well as Istanbul's code coverage reports (interactive HTML).
+                js.append(ts_)
+
             path = file.path[len(lib.path + "/"):]
             if declaration_prefix:
                 path = "%s/%s" % (declaration_prefix, path)
diff --git a/typescript/rules.bzl b/typescript/rules.bzl
index 9952f31..41d8c1a 100644
--- a/typescript/rules.bzl
+++ b/typescript/rules.bzl
@@ -245,6 +245,12 @@ def _ts_library_impl(ctx):
                     map = actions.declare_file(map_path(js_path(js_path_, jsx)))
                     js.append(map)
                     js_outputs.append(map)
+
+                    # Include .ts file with source map. Used by VSCode debugger
+                    # as well as Istanbul's code coverage reports (interactive
+                    # HTML).
+                    js.append(ts_)
+
                 declaration = actions.declare_file(declaration_path(declaration_path_))
                 declarations.append(declaration)
                 outputs.append(declaration)