metro-bundler: stricter TransformedCodeFile type and fix use sites

Summary: Here's a good example why Flow "exact types" are useful: there are a few place where we were adding unusused fields in the objects. As these fields end up in JSON files used to communicate with Buck, this can amount to a waste of resources. This changeset make the type exact and removes the unused fields.

Reviewed By: mjesun

Differential Revision: D6159350

fbshipit-source-id: 8cdf29d5729253f119778943ad961eacb8990c04

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

@@ -152,13 +152,13 @@ export type TransformResults = {[string]: TransformResult};
 
 export type TransformVariants = {+[name: string]: {}, +default: {}};
 
-export type TransformedCodeFile = {
+export type TransformedCodeFile = {|
   +file: string,
   +hasteID: ?string,
   package?: PackageData,
   +transformed: TransformResults,
   +type: CodeFileTypes,
-};
+|};
 
 export type ImageSize = {|+width: number, +height: number|};
 

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

@@ -49,12 +49,11 @@ describe('transforming JS modules:', () => {
     ast: t.file(t.program(body)),
   });
 
-  it('passes through file name and code', () => {
+  it('passes through file name', () => {
     const result = transformModule(sourceCode, options());
     expect(result.type).toBe('code');
     expect(result.details).toEqual(
       expect.objectContaining({
-        code: sourceCode,
         file: filename,
       }),
     );

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

@@ -99,8 +99,6 @@ function transformModule(
 
   return {
     details: {
-      assetContent: null,
-      code,
       file: filename,
       hasteID: hasteID || null,
       transformed,
@@ -129,8 +127,6 @@ function transformJSON(json, options): TransformedSourceFile {
   );
 
   const result: TransformedCodeFile = {
-    assetContent: null,
-    code: json,
     file: filename,
     hasteID: value.name,
     transformed,