Emit x_google_ignoreList, add serializer.isThirdPartyModule config …

…option

Summary:
Changelog:

* **[Feature]**: Support [`x_google_ignoreList`](https://developer.chrome.com/articles/x-google-ignore-list/) source map extension.

Emits `x_google_ignoreList` as part of Metro's source maps in order to support ["Just My Code"](https://developer.chrome.com/blog/devtools-modern-web-debugging/#just-my-code) debugging in Chrome DevTools and other compatible debuggers.

By default, the ignore list consists of modules whose code was generated directly by Metro, and any module whose path contains a `node_modules` component. The latter is configurable using the new `serializer.isThirdPartyModule` option.

The infrastructure for working with the `x_google_ignoreList` field was added and tested in D43554204.

Reviewed By: GijsWeterings

Differential Revision: D43555494

fbshipit-source-id: ca614994599600dfaff21a59cb2106590873e090

docs/Configuration.md

@@ -576,6 +576,18 @@ Type: `(module: Array<Module>) => boolean`
 
 A filter function to discard specific modules from the output.
 
+#### `isThirdPartyModule`
+
+Type: `(module: {path: string, ...}) => boolean`
+
+A function that determines which modules are added to the [`x_google_ignoreList`](https://developer.chrome.com/articles/x-google-ignore-list/) field of the source map. This supports ["Just My Code"](https://developer.chrome.com/blog/devtools-modern-web-debugging/#just-my-code) debugging in Chrome DevTools and other compatible debuggers.
+
+Defaults to returning `true` for modules with a path component named `node_modules`.
+
+:::note
+In addition to modules marked as ignored by `isThirdPartyModule`, Metro will also automatically add modules generated by the bundler itself to the ignore list.
+:::
+
 ---
 ### Server Options
 

docs/SourceMapFormat.md

@@ -135,3 +135,7 @@ decoded.push({column, name: names[nameIndex] /* 'b' */, line});
   ]
 */
 ```
+
+## `x_google_ignoreList`
+
+Metro's source maps include the [`x_google_ignoreList`](https://developer.chrome.com/articles/x-google-ignore-list/) field by default. The [`serializer.isThirdPartyModule`](./Configuration.md#isthirdpartymodule) option can be used to control which modules are ignore-listed.

packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap

@@ -93,6 +93,7 @@ Object {
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
     "getRunModuleStatement": [Function],
+    "isThirdPartyModule": [Function],
     "polyfillModuleNames": Array [],
     "processModuleFilter": [Function],
   },
@@ -271,6 +272,7 @@ Object {
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
     "getRunModuleStatement": [Function],
+    "isThirdPartyModule": [Function],
     "polyfillModuleNames": Array [],
     "processModuleFilter": [Function],
   },
@@ -449,6 +451,7 @@ Object {
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
     "getRunModuleStatement": [Function],
+    "isThirdPartyModule": [Function],
     "polyfillModuleNames": Array [],
     "processModuleFilter": [Function],
   },
@@ -627,6 +630,7 @@ Object {
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
     "getRunModuleStatement": [Function],
+    "isThirdPartyModule": [Function],
     "polyfillModuleNames": Array [],
     "processModuleFilter": [Function],
   },

packages/metro-config/src/configTypes.flow.js

@@ -139,6 +139,7 @@ type SerializerConfigT = {
   getRunModuleStatement: (number | string) => string,
   polyfillModuleNames: $ReadOnlyArray<string>,
   processModuleFilter: (modules: Module<>) => boolean,
+  isThirdPartyModule: (module: $ReadOnly<{path: string, ...}>) => boolean,
 };
 
 type TransformerConfigT = {

packages/metro-config/src/defaults/index.js

@@ -68,6 +68,8 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
     createModuleIdFactory: defaultCreateModuleIdFactory,
     experimentalSerializerHook: () => {},
     customSerializer: null,
+    isThirdPartyModule: module =>
+      /(?:^|[/\\])node_modules[/\\]/.test(module.path),
   },
 
   server: {

packages/metro-config/types/configTypes.d.ts

@@ -136,6 +136,7 @@ export interface SerializerConfigT {
   getRunModuleStatement: (moduleId: number | string) => string;
   polyfillModuleNames: ReadonlyArray<string>;
   processModuleFilter: (modules: Module) => boolean;
+  isThirdPartyModule: (module: {readonly path: string}) => boolean;
 }
 
 export interface TransformerConfigT extends JsTransformerConfig {

packages/metro-source-map/src/__tests__/source-map-test.js

@@ -63,6 +63,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code1',
         path: 'path1',
+        isIgnored: false,
       },
       {
         code: lines(3),
@@ -73,6 +74,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code2',
         path: 'path2',
+        isIgnored: true,
       },
       {
         code: lines(23),
@@ -85,6 +87,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code3',
         path: 'path3',
+        isIgnored: false,
       },
     ];
 
@@ -99,6 +102,7 @@ describe('build map from raw mappings', () => {
         [{names: ['<global>'], mappings: 'AAA'}],
         null,
       ],
+      x_google_ignoreList: [1],
       version: 3,
     });
   });
@@ -129,6 +133,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code1',
         path: 'path1',
+        isIgnored: false,
       },
       {
         code: lines(3),
@@ -139,6 +144,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code2',
         path: 'path2',
+        isIgnored: false,
       },
       {
         code: lines(23),
@@ -151,6 +157,7 @@ describe('build map from raw mappings', () => {
         ],
         source: 'code3',
         path: 'path3',
+        isIgnored: false,
       },
     ];
 

packages/metro-source-map/src/source-map.js

@@ -106,7 +106,8 @@ function fromRawMappingsImpl(
     +path: string,
     +source: string,
     +code: string,
-    ...
+    +isIgnored: boolean,
+    +lineCount?: number,
   }>,
   offsetLines: number,
 ): void {
@@ -173,7 +174,8 @@ function fromRawMappings(
     +path: string,
     +source: string,
     +code: string,
-    ...
+    +isIgnored: boolean,
+    +lineCount?: number,
   }>,
   offsetLines: number = 0,
 ): Generator {
@@ -199,7 +201,8 @@ async function fromRawMappingsNonBlocking(
     +path: string,
     +source: string,
     +code: string,
-    ...
+    +isIgnored: boolean,
+    +lineCount?: number,
   }>,
   offsetLines: number = 0,
 ): Promise<Generator> {
@@ -274,11 +277,14 @@ function addMappingsForFile(
     +map: ?Array<MetroSourceMapSegmentTuple>,
     +path: string,
     +source: string,
-    ...
+    +isIgnored: boolean,
+    +lineCount?: number,
   },
   carryOver: number,
 ) {
-  generator.startFile(module.path, module.source, module.functionMap);
+  generator.startFile(module.path, module.source, module.functionMap, {
+    addToIgnoreList: module.isIgnored,
+  });
 
   for (let i = 0, n = mappings.length; i < n; ++i) {
     addMapping(generator, mappings[i], carryOver);

packages/metro-transform-worker/src/index.js

@@ -195,7 +195,16 @@ const minifyCode = async (
   ...
 }> => {
   const sourceMap = fromRawMappings([
-    {code, source, map, functionMap: null, path: filename},
+    {
+      code,
+      source,
+      map,
+      // functionMap is overridden by the serializer
+      functionMap: null,
+      path: filename,
+      // isIgnored is overriden by the serializer
+      isIgnored: false,
+    },
   ]).toMap(undefined, {});
 
   const minify = getMinifier(config.minifierPath);