Adds an experimental hook for custom resolutions

Reviewed By: mjesun

Differential Revision: D7337022

fbshipit-source-id: fea1ee345e4d3b5713fed6cdc33869fbba6f21e2

packages/metro-resolver/src/index.js

@@ -18,6 +18,7 @@ export type {
 } from './resolve';
 export type {
   AssetFileResolution,
+  CustomResolver,
   FileAndDirCandidates,
   FileCandidates,
   FileResolution,

packages/metro-resolver/src/resolve.js

@@ -20,6 +20,7 @@ const path = require('path');
 
 import type {
   AssetFileResolution,
+  CustomResolver,
   FileAndDirCandidates,
   FileCandidates,
   FileResolution,
@@ -29,9 +30,10 @@ import type {
 
 export type ResolutionContext = ModulePathContext &
   HasteContext & {
-    originModulePath: string,
     allowHaste: boolean,
     extraNodeModules: ?{[string]: string},
+    originModulePath: string,
+    resolveRequest?: ?CustomResolver,
   };
 
 function resolve(
@@ -39,9 +41,13 @@ function resolve(
   moduleName: string,
   platform: string | null,
 ): Resolution {
-  if (isRelativeImport(moduleName) || isAbsolutePath(moduleName)) {
+  if (
+    !context.resolveRequest &&
+    (isRelativeImport(moduleName) || isAbsolutePath(moduleName))
+  ) {
     return resolveModulePath(context, moduleName, platform);
   }
+
   const realModuleName = context.redirectModulePath(moduleName);
   // exclude
   if (realModuleName === false) {
@@ -49,7 +55,10 @@ function resolve(
   }
 
   const {originModulePath} = context;
-  if (isRelativeImport(realModuleName) || isAbsolutePath(realModuleName)) {
+  if (
+    !context.resolveRequest &&
+    (isRelativeImport(realModuleName) || isAbsolutePath(realModuleName))
+  ) {
     // derive absolute path /.../node_modules/originModuleDir/realModuleName
     const fromModuleParentIdx =
       originModulePath.lastIndexOf('node_modules' + path.sep) + 13;
@@ -61,8 +70,18 @@ function resolve(
     return resolveModulePath(context, absPath, platform);
   }
 
-  // At that point we only have module names that
+  if (context.resolveRequest) {
-  // aren't relative paths nor absolute paths.
+    try {
+      const resolution = context.resolveRequest(
+        moduleName,
+        context.originModulePath,
+      );
+      if (resolution) {
+        return {type: 'sourceFile', filePath: resolution};
+      }
+    } catch (error) {}
+  }
+
   if (context.allowHaste) {
     const normalizedName = normalizePath(realModuleName);
     const result = resolveHasteName(context, normalizedName, platform);

packages/metro-resolver/src/types.js

@@ -42,3 +42,5 @@ export type FileCandidates =
     +filePathPrefix: string,
     +candidateExts: $ReadOnlyArray<string>,
   |};
+
+export type CustomResolver = (string, string) => string;

packages/metro/src/Bundler/index.js

@@ -36,6 +36,7 @@ import type {Reporter} from '../lib/reporting';
 import type Module from '../node-haste/Module';
 import type {BabelSourceMap} from '@babel/core';
 import type {CacheStore} from 'metro-cache';
+import type {CustomResolver} from 'metro-resolver';
 import type {
   MetroSourceMapSegmentTuple,
   MetroSourceMap,
@@ -98,6 +99,7 @@ export type Options = {|
   +providesModuleNodeModules?: Array<string>,
   +reporter: Reporter,
   +resetCache: boolean,
+  +resolveRequest: ?CustomResolver,
   +sourceExts: Array<string>,
   +transformCache: TransformCache,
   +transformModulePath: string,
@@ -163,6 +165,7 @@ class Bundler {
       providesModuleNodeModules:
         opts.providesModuleNodeModules || defaults.providesModuleNodeModules,
       reporter: opts.reporter,
+      resolveRequest: opts.resolveRequest,
       resetCache: opts.resetCache,
       sourceExts: opts.sourceExts,
       transformCode: this._cachedTransformCode.bind(this),

packages/metro/src/Config.js

@@ -23,6 +23,7 @@ import type {TransformedCode} from './JSTransformer/worker';
 import type {DynamicRequiresBehavior} from './ModuleGraph/worker/collectDependencies';
 import type {IncomingMessage, ServerResponse} from 'http';
 import type {CacheStore} from 'metro-cache';
+import type {CustomResolver} from 'metro-resolver';
 
 type Middleware = (IncomingMessage, ServerResponse, ?() => mixed) => mixed;
 
@@ -141,6 +142,12 @@ export type ConfigT = {
    */
   postProcessBundleSourcemap: PostProcessBundleSourcemap,
 
+  /**
+   * An optional function used to resolve requests. Ignored when the request can
+   * be resolved through Haste.
+   */
+  resolveRequest: ?CustomResolver,
+
   /**
    * Path to a require-able module that exports:
    * - a `getHasteName(filePath)` method that returns `hasteName` for module at
@@ -186,6 +193,7 @@ const DEFAULT = ({
   getUseGlobalHotkey: () => true,
   postMinifyProcess: x => x,
   postProcessBundleSourcemap: ({code, map, outFileName}) => ({code, map}),
+  resolveRequest: null,
   getModulesRunBeforeMainModule: () => [],
   getWorkerPath: () => null,
 }: ConfigT);

packages/metro/src/ModuleGraph/node-haste/node-haste.js

@@ -29,10 +29,12 @@ const {ModuleMap} = require('jest-haste-map');
 import type {Moduleish} from '../../node-haste/DependencyGraph/ResolutionRequest';
 import type {ResolveFn, TransformedCodeFile} from '../types.flow';
 import type {Extensions, Path} from './node-haste.flow';
+import type {CustomResolver} from 'metro-resolver';
 
 type ResolveOptions = {|
   assetExts: Extensions,
   extraNodeModules: {[id: string]: string},
+  resolveRequest?: ?CustomResolver,
   +sourceExts: Extensions,
   transformedFiles: {[path: Path]: TransformedCodeFile},
 |};
@@ -147,6 +149,7 @@ exports.createResolveFn = function(options: ResolveOptions): ResolveFn {
     preferNativePlatform: true,
     resolveAsset: (dirPath, assetName, platform) =>
       assetResolutionCache.resolve(dirPath, assetName, platform),
+    resolveRequest: options.resolveRequest,
     sourceExts,
   });
 

packages/metro/src/Server/index.js

@@ -54,6 +54,7 @@ import type {
 } from '../Bundler';
 import type {CacheStore} from 'metro-cache';
 import type {Delta, Graph} from '../DeltaBundler';
+import type {CustomResolver} from 'metro-resolver';
 import type {MetroSourceMap} from 'metro-source-map';
 import type {TransformCache} from '../lib/TransformCaching';
 import type {Symbolicate} from './symbolicate/symbolicate';
@@ -102,6 +103,7 @@ class Server {
     maxWorkers: number,
     minifierPath: string,
     platforms: Array<string>,
+    resolveRequest: ?CustomResolver,
     polyfillModuleNames: Array<string>,
     postMinifyProcess: PostMinifyProcess,
     postProcessBundleSourcemap: PostProcessBundleSourcemap,
@@ -109,6 +111,7 @@ class Server {
     providesModuleNodeModules?: Array<string>,
     reporter: Reporter,
     resetCache: boolean,
+    resolveRequest: ?CustomResolver,
     +getModulesRunBeforeMainModule: (entryFilePath: string) => Array<string>,
     +getRunModuleStatement: (number | string) => string,
     silent: boolean,
@@ -177,6 +180,7 @@ class Server {
       providesModuleNodeModules: options.providesModuleNodeModules,
       reporter,
       resetCache: options.resetCache || false,
+      resolveRequest: options.resolveRequest,
       silent: options.silent || false,
       sourceExts: options.assetTransforms
         ? sourceExts.concat(assetExts)

packages/metro/src/index.js

@@ -141,6 +141,7 @@ async function runMetro({
     providesModuleNodeModules,
     resetCache,
     reporter,
+    resolveRequest: normalizedConfig.resolveRequest,
     sourceExts: normalizedConfig.assetTransforms
       ? sourceExts.concat(assetExts)
       : sourceExts,

packages/metro/src/legacy.js

@@ -196,6 +196,7 @@ function toServerOptions(options: Options): ServerOptions {
     providesModuleNodeModules: options.providesModuleNodeModules,
     reporter: options.reporter,
     resetCache: options.resetCache,
+    resolveRequest: options.resolveRequest,
     silent: options.silent,
     sourceExts: options.sourceExts,
     transformCache: options.transformCache || TransformCaching.useTempDir(),

packages/metro/src/node-haste/DependencyGraph.js

@@ -40,6 +40,7 @@ import type {ModuleMap} from './DependencyGraph/ModuleResolution';
 import type {TransformCode} from './Module';
 import type Package from './Package';
 import type {HasteFS} from './types';
+import type {CustomResolver} from 'metro-resolver';
 
 type Options = {|
   +assetExts: Array<string>,
@@ -58,6 +59,7 @@ type Options = {|
   +providesModuleNodeModules: Array<string>,
   +reporter: Reporter,
   +resetCache: boolean,
+  +resolveRequest: ?CustomResolver,
   +sourceExts: Array<string>,
   +transformCache: TransformCache,
   +transformCode: TransformCode,
@@ -192,6 +194,7 @@ class DependencyGraph extends EventEmitter {
       preferNativePlatform: true,
       resolveAsset: (dirPath, assetName, platform) =>
         this._assetResolutionCache.resolve(dirPath, assetName, platform),
+      resolveRequest: this._opts.resolveRequest,
       sourceExts: this._opts.sourceExts,
     });
   }

packages/metro/src/node-haste/DependencyGraph/ModuleResolution.js

@@ -17,6 +17,7 @@ const path = require('path');
 const util = require('util');
 
 import type {
+  CustomResolver,
   DoesFileExist,
   IsAssetFile,
   ResolveAsset,
@@ -70,6 +71,7 @@ type Options<TModule, TPackage> = {|
   +preferNativePlatform: boolean,
   +moduleMap: ModuleMap,
   +resolveAsset: ResolveAsset,
+  +resolveRequest: ?CustomResolver,
   +sourceExts: Array<string>,
 |};
 

packages/metro/src/shared/types.flow.js

@@ -23,6 +23,7 @@ import type {GlobalTransformCache} from '../lib/GlobalTransformCache';
 import type {TransformCache} from '../lib/TransformCaching';
 import type {Reporter} from '../lib/reporting';
 import type {CacheStore} from 'metro-cache';
+import type {CustomResolver} from 'metro-resolver';
 import type {
   MetroSourceMap,
   MetroSourceMapSegmentTuple,
@@ -102,6 +103,7 @@ export type Options = {|
   providesModuleNodeModules?: Array<string>,
   reporter?: Reporter,
   resetCache?: boolean,
+  resolveRequest: ?CustomResolver,
   +getModulesRunBeforeMainModule: (entryPoint: string) => Array<string>,
   silent?: boolean,
   +sourceExts: ?Array<string>,