Separate build modules from require calls when bundling

Summary: separates modules of the dependency graph from the generated require calls to kick of the app. This is required to make RAM bundle generation work properly'

Reviewed By: jeanlauliac

Differential Revision: D5094635

fbshipit-source-id: fca69a3e2d9b030cdc4d4405c2b5e795b0d55f87

packages/metro-bundler/src/ModuleGraph/output/as-plain-bundle.js

@@ -17,13 +17,18 @@ const {addModuleIdsToModuleWrapper} = require('./util');
 
 import type {OutputFn} from '../types.flow';
 
-module.exports = (
+function asPlainBundle({
-  (modules, filename, idForPath, sourceMapPath) => {
+  filename,
+  idForPath,
+  modules,
+  requireCalls,
+  sourceMapPath,
+}) {
   let code = '';
   let line = 0;
   const sections = [];
 
-    for (const module of modules) {
+  for (const module of concat(modules, requireCalls)) {
     const {file} = module;
     const moduleCode = file.type === 'module'
       ? addModuleIdsToModuleWrapper(module, idForPath)
@@ -48,10 +53,18 @@ module.exports = (
     extraFiles: [[`${filename}.meta`, meta(code)]],
     map: createIndexMap({file: filename, sections}),
   };
-  }: OutputFn);
+}
+
+module.exports = (asPlainBundle: OutputFn);
 
 const reLine = /^/gm;
 function countLines(string: string): number {
   //$FlowFixMe This regular expression always matches
   return string.match(reLine).length;
 }
+
+function* concat<T>(...iterables: Array<Iterable<T>>): Iterable<T> {
+  for (const it of iterables) {
+    yield* it;
+  }
+}

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

@@ -70,16 +70,17 @@ export type Module = {|
   file: File,
 |};
 
-export type OutputFn = (
+export type OutputFn = ({|
-  modules: Iterable<Module>,
   filename: string,
   idForPath: IdForPathFn,
+  modules: Iterable<Module>,
+  requireCalls: Iterable<Module>,
   sourceMapPath?: string,
-) => OutputResult;
+|}) => OutputResult;
 
 type OutputResult = {|
   code: string | Buffer,
-  extraFiles: Iterable<[string, string | Buffer]>,
+  extraFiles?: Iterable<[string, string | Buffer]>,
   map: SourceMap,
 |};