[loader] Never return a generator, use JSON where possible

packages/embedded-document-artefact-loader/src/__tests__/webpack.test.ts

@@ -197,7 +197,7 @@ describe("webpackLoader", () => {
       const result = await runLoader(source);
       const transpiled = result.result![0]?.toString();
       const sourceMap = result.result![1];
-      const consumer = new SourceMapConsumer(sourceMap!.toString() as any);
+      const consumer = new SourceMapConsumer(sourceMap! as any);
 
       expect(
         getGeneratedCodeForOriginalRange(
@@ -225,7 +225,7 @@ describe("webpackLoader", () => {
       const result = await runLoader(source);
       const transpiled = result.result![0]?.toString();
       const sourceMap = result.result![1];
-      const consumer = new SourceMapConsumer(sourceMap!.toString() as any);
+      const consumer = new SourceMapConsumer(sourceMap! as any);
 
       // fs.writeFileSync(__dirname + "/tmp/test.out", transpiled!);
       // fs.writeFileSync(__dirname + "/tmp/test.map", sourceMap!);
@@ -256,7 +256,7 @@ describe("webpackLoader", () => {
       const result = await runLoader(source);
       const transpiled = result.result![0]?.toString();
       const sourceMap = result.result![1];
-      const consumer = new SourceMapConsumer(sourceMap!.toString() as any);
+      const consumer = new SourceMapConsumer(sourceMap! as any);
 
       expect(
         consumer.generatedPositionFor({
@@ -297,7 +297,7 @@ describe("webpackLoader", () => {
       const result = await runLoader(source, { compileTS: true });
       const transpiled = result.result![0]?.toString();
       const sourceMap = result.result![1];
-      const consumer = new SourceMapConsumer(sourceMap!.toString() as any);
+      const consumer = new SourceMapConsumer(sourceMap! as any);
 
       expect(
         getGeneratedCodeForOriginalRange(

packages/embedded-document-artefact-loader/src/source-map-utils.ts

@@ -4,17 +4,17 @@ import {
   RawSourceMap,
 } from "source-map-js";
 
+function toRawSourceMap(sourceMap: string | RawSourceMap): RawSourceMap {
+  return typeof sourceMap === "string" ? JSON.parse(sourceMap) : sourceMap;
+}
+
 export function applySourceMap(
   sourcePath: string,
   previousSourceMap: string | RawSourceMap,
-  nextSourceMap: string,
+  nextSourceMap: string | RawSourceMap,
 ): SourceMapGenerator {
-  const prev = new SourceMapConsumer(
-    typeof previousSourceMap === "string"
-      ? JSON.parse(previousSourceMap)
-      : previousSourceMap,
-  );
-  const next = new SourceMapConsumer(JSON.parse(nextSourceMap));
+  const prev = new SourceMapConsumer(toRawSourceMap(previousSourceMap));
+  const next = new SourceMapConsumer(toRawSourceMap(nextSourceMap));
   const pipeline = SourceMapGenerator.fromSourceMap(next);
   pipeline.applySourceMap(prev, sourcePath);
   return pipeline;

packages/embedded-document-artefact-loader/src/ts-jest.ts

@@ -79,7 +79,7 @@ function extractAndApplySourceMap(
     //       ourselves rather than letting jest do the work.
     tsResult = {
       code: tsResultCode,
-      map: applySourceMap(sourcePath, sourceMap.toString(), tsResultMap) as any, // SourceMapGenerator seems to satisfy the runtime needs, but it's unclear which properties it uses exactly
+      map: applySourceMap(sourcePath, sourceMap.toJSON(), tsResultMap) as any, // SourceMapGenerator seems to satisfy the runtime needs, but it's unclear which properties it uses exactly
     };
   }
   return tsResult;

packages/embedded-document-artefact-loader/src/webpack.ts

@@ -1,5 +1,5 @@
 import type { LoaderDefinitionFunction } from "webpack";
-import { SourceMapConsumer, SourceMapGenerator } from "source-map-js";
+import { SourceMapGenerator } from "source-map-js";
 import { transform } from "./transform";
 import { applySourceMap } from "./source-map-utils";
 
@@ -27,11 +27,11 @@ const webpackLoader: LoaderDefinitionFunction = function (
       applySourceMap(
         this.resourcePath,
         inputSourceMap as string,
-        sourceMap.toString(),
-      ) as any, // SourceMapGenerator seems to satisfy the runtime needs, but it's unclear which properties it uses exactly
+        sourceMap.toJSON(),
+      ).toJSON(),
     );
   } else if (transformed && sourceMap) {
-    callback(null, transformed, sourceMap as any); // SourceMapGenerator seems to satisfy the runtime needs, but it's unclear which properties it uses exactly
+    callback(null, transformed, sourceMap.toJSON());
   } else if (transformed) {
     callback(null, transformed, inputSourceMap);
   } else {

patches/source-map-js+1.0.2.patch

@@ -0,0 +1,21 @@
+diff --git a/node_modules/source-map-js/source-map.d.ts b/node_modules/source-map-js/source-map.d.ts
+index 9f8a4b3..2117555 100644
+--- a/node_modules/source-map-js/source-map.d.ts
++++ b/node_modules/source-map-js/source-map.d.ts
+@@ -5,7 +5,7 @@ declare module 'source-map-js' {
+     }
+ 
+     export interface RawSourceMap extends StartOfSourceMap {
+-        version: string;
++        version: number;
+         sources: string[];
+         names: string[];
+         sourcesContent?: string[];
+@@ -75,6 +75,7 @@ declare module 'source-map-js' {
+         setSourceContent(sourceFile: string, sourceContent: string): void;
+         applySourceMap(sourceMapConsumer: SourceMapConsumer, sourceFile?: string, sourceMapPath?: string): void;
+         toString(): string;
++        toJSON(): RawSourceMap;
+     }
+ 
+     export interface CodeWithSourceMap {