packager: buck: transform-module: add support for assets

Reviewed By: davidaurelio

Differential Revision: D4868312

fbshipit-source-id: 44d20a5ed73637a9b3f43a99b5c82931f3e15dc6

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

@@ -30,7 +30,7 @@ export type File = {|
   type: FileTypes,
 |};
 
-type FileTypes = 'module' | 'script';
+type FileTypes = 'module' | 'script' | 'asset';
 
 export type GraphFn = (
   entryPoints: Iterable<string>,

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

@@ -48,6 +48,11 @@ function transformModule(
     return;
   }
 
+  if (options.filename.endsWith('.png')) {
+    transformAsset(code, options, callback);
+    return;
+  }
+
   const {filename, transformer, variants = defaultVariants} = options;
   const tasks = {};
   Object.keys(variants).forEach(name => {
@@ -114,7 +119,7 @@ function transformJSON(json, options, callback) {
     file: filename,
     hasteID: value.name,
     transformed,
-    type: 'module',
+    type: 'asset',
   };
 
   if (basename(filename) === 'package.json') {
@@ -128,6 +133,16 @@ function transformJSON(json, options, callback) {
   callback(null, result);
 }
 
+function transformAsset(data, options, callback) {
+  callback(null, {
+    code: data,
+    file: options.filename,
+    hasteID: null,
+    transformed: {},
+    type: 'module',
+  });
+}
+
 function makeResult(ast, filename, sourceCode, isPolyfill = false) {
   let dependencies, dependencyMapName, file;
   if (isPolyfill) {