packager: correct transform for assets to avoid string

Reviewed By: davidaurelio

Differential Revision: D4913509

fbshipit-source-id: 9997da819483056d896fedecdc47510ecd381c03

packages/metro-bundler/src/ModuleGraph/types.flow.js

@@ -126,6 +126,7 @@ export type TransformResults = {[string]: TransformResult};
 export type TransformVariants = {[key: string]: Object};
 
 export type TransformedFile = {
+  assetContent: ?string,
   code: string,
   file: string,
   hasteID: ?string,

packages/metro-bundler/src/ModuleGraph/worker/__tests__/wrap-worker-fn-test.js

@@ -33,9 +33,9 @@ describe('wrapWorkerFn:', () => {
   const fs = require('fs');
   const mkdirp = require('mkdirp');
 
-  it('reads the passed-in file synchronously as UTF-8', done => {
+  it('reads the passed-in file synchronously as buffer', done => {
     wrapped(infile, outfile, {}, () => {
-      expect(fs.readFileSync).toBeCalledWith(infile, 'utf8');
+      expect(fs.readFileSync).toBeCalledWith(infile);
       done();
     });
   });

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

@@ -39,17 +39,18 @@ const moduleFactoryParameters = ['global', 'require', 'module', 'exports'];
 const polyfillFactoryParameters = ['global'];
 
 function transformModule(
-  code: string,
+  content: Buffer,
   options: TransformOptions,
   callback: Callback<TransformedFile>,
 ): void {
-  if (options.filename.endsWith('.json')) {
-    transformJSON(code, options, callback);
+  if (options.filename.endsWith('.png')) {
+    transformAsset(content, options, callback);
     return;
   }
 
-  if (options.filename.endsWith('.png')) {
-    transformAsset(code, options, callback);
+  const code = content.toString('utf8');
+  if (options.filename.endsWith('.json')) {
+    transformJSON(code, options, callback);
     return;
   }
 
@@ -85,6 +86,7 @@ function transformModule(
     const annotations = docblock.parseAsObject(docblock.extract(code));
 
     callback(null, {
+      assetContent: null,
       code,
       file: filename,
       hasteID: annotations.providesModule || null,
@@ -115,6 +117,7 @@ function transformJSON(json, options, callback) {
     .forEach(key => (transformed[key] = moduleData));
 
   const result: TransformedFile = {
+    assetContent: null,
     code: json,
     file: filename,
     hasteID: value.name,
@@ -133,9 +136,14 @@ function transformJSON(json, options, callback) {
   callback(null, result);
 }
 
-function transformAsset(data, options, callback) {
+function transformAsset(
+  content: Buffer,
+  options: TransformOptions,
+  callback: Callback<TransformedFile>,
+) {
   callback(null, {
-    code: data,
+    assetContent: content.toString('base64'),
+    code: '',
     file: options.filename,
     hasteID: null,
     transformed: {},

packages/metro-bundler/src/ModuleGraph/worker/wrap-worker-fn.js

@@ -19,7 +19,7 @@ import type {Callback} from '../types.flow';
 
 type Path = string;
 type WorkerFn<Options> = (
-  fileContents: string,
+  fileContents: Buffer,
   options: Options,
   callback: Callback<Object>,
 ) => void;
@@ -39,7 +39,7 @@ function wrapWorkerFn<Options>(
     options: Options,
     callback: Callback<>,
   ) => {
-    const contents = fs.readFileSync(infile, 'utf8');
+    const contents = fs.readFileSync(infile);
     workerFunction(contents, options, (error, result) => {
       if (error) {
         callback(error);