Call minification post-processing hook

Summary: RN configuration allows to specify a post-minify hook. This wasn’t called in the new Buck integration so far. Added here.

Reviewed By: cpojer

Differential Revision: D5087325

fbshipit-source-id: 74b58bd3a203716d8f01b5d7ba552b6ad1b575ce

packages/metro-bundler/src/ModuleGraph/worker/__tests__/optimize-module-test.js

@@ -14,6 +14,7 @@ const optimizeModule = require('../optimize-module');
 const transformModule = require('../transform-module');
 const transformer = require('../../../../transformer.js');
 const {SourceMapConsumer} = require('source-map');
+const {fn} = require('../../test-helpers');
 
 const {objectContaining} = jasmine;
 
@@ -22,6 +23,7 @@ describe('optimizing JS modules', () => {
   const optimizationOptions = {
     dev: false,
     platform: 'android',
+    postMinifyProcess: x => x,
   };
   const originalCode =
     `if (Platform.OS !== 'android') {
@@ -85,6 +87,30 @@ describe('optimizing JS modules', () => {
     });
   });
 
+  describe('post-processing', () => {
+    let postMinifyProcess, optimize;
+    beforeEach(() => {
+      postMinifyProcess = fn();
+      optimize = () =>
+        optimizeModule(transformResult, {...optimizationOptions, postMinifyProcess});
+    });
+
+    it('passes the result to the provided postprocessing function', () => {
+      postMinifyProcess.stub.callsFake(x => x);
+      const result = optimize();
+      const {code, map} = result.details.transformed.default;
+      expect(postMinifyProcess).toBeCalledWith({code, map});
+    });
+
+    it('uses the result of the provided postprocessing function for the result', () => {
+      const code = 'var postprocessed = "code";';
+      const map = {version: 3, mappings: 'postprocessed'};
+      postMinifyProcess.stub.returns({code, map});
+      expect(optimize().details.transformed.default)
+        .toEqual(objectContaining({code, map}));
+    });
+  });
+
   it('passes through non-code data unmodified', () => {
     const data = {type: 'asset', details: {arbitrary: 'data'}};
     expect(optimizeModule(JSON.stringify(data), {dev: true, platform: ''}))

packages/metro-bundler/src/ModuleGraph/worker/optimize-module.js

@@ -20,11 +20,14 @@ const sourceMap = require('source-map');
 
 import type {TransformedSourceFile, TransformResult} from '../types.flow';
 import type {MappingsMap, SourceMap} from '../../lib/SourceMap';
+import type {PostMinifyProcess} from '../../Bundler/index.js';
+
 
 export type OptimizationOptions = {|
   dev: boolean,
   isPolyfill?: boolean,
   platform: string,
+  postMinifyProcess: PostMinifyProcess,
 |};
 
 function optimizeModule(
@@ -40,16 +43,21 @@ function optimizeModule(
   const {details} = data;
   const {code, file, transformed} = details;
   const result = {...details, transformed: {}};
+  const {postMinifyProcess} = optimizationOptions;
 
   //$FlowIssue #14545724
   Object.entries(transformed).forEach(([k, t: TransformResult]: [*, TransformResult]) => {
-    result.transformed[k] = optimize(t, file, code, optimizationOptions);
+    const optimized = optimize(t, file, code, optimizationOptions);
+    const processed = postMinifyProcess({code: optimized.code, map: optimized.map});
+    optimized.code = processed.code;
+    optimized.map = processed.map;
+    result.transformed[k] = optimized;
   });
 
   return {type: 'code', details: result};
 }
 
-function optimize(transformed, file, originalCode, options): TransformResult {
+function optimize(transformed, file, originalCode, options) {
   const {code, dependencyMapName, map} = transformed;
   const optimized = optimizeCode(code, map, file, options);