fix: fix browser replacement on direct resource require

Author: 3cp

spec/package-reader.spec.js

@@ -509,6 +509,39 @@ test('packageReader reads browser replacement in package.json', t => {
   });
 });
 
+test('packageReader uses browser replacement in package.json to normalize resource read', t => {
+  getReader('foo', {
+    'node_modules/foo/package.json': `{
+      "name": "foo",
+      "main": "index",
+      "browser": {
+        "module-a": false,
+        "module-b.js": "./shims/module/b.js",
+        "./server/only.js": "./shims/client-only.js"
+      }
+    }`,
+    'node_modules/foo/shims/client-only.js': "require('module-a');require('module-b.js');require('module-c');"
+  }).then(r => {
+    r.readResource('server/only').then(
+      unit => {
+        t.deepEqual(unit, {
+          path: 'node_modules/foo/shims/client-only.js',
+          contents: "require('__ignore__');require('./module/b');require('module-c');",
+          moduleId: 'foo/shims/client-only',
+          packageName: 'foo'
+        });
+
+        t.equal(r.name, 'foo');
+        t.equal(r.mainPath, 'index.js');
+      },
+      err => {
+        t.fail(err.message);
+      }
+    ).then(t.end);
+  });
+});
+
+
 test('packageReader uses browser replacement in package.json to normalize file contents', t => {
   getReader('foo', {
     'node_modules/foo/package.json': `{

src/index.js

@@ -160,7 +160,7 @@ export default class Bundler {
           return reader.readMain()
           .then(unit => this.capture(unit))
           .then(tracedUnit => {
-            this._ensureNpmMainAlias(tracedUnit, pkg.name);
+            this._ensureNpmAlias(tracedUnit, pkg.name);
           });
         }
       });
@@ -186,7 +186,10 @@ export default class Bundler {
     })
   }
 
-  _ensureNpmMainAlias(tracedUnit, id) {
+  // this ensures alias to package main, and alias to direct require
+  // to some browser replacement.
+  // e.g. readable-stream/readable -> readable-stream/readable-browser
+  _ensureNpmAlias(tracedUnit, id) {
     if (this._moduleId_done.has(id)) return;
 
     const defined = tracedUnit.defined;
@@ -290,7 +293,7 @@ export default class Bundler {
           .then(unit => this.capture(unit))
           .then(tracedUnit => {
             if (!resource) {
-              this._ensureNpmMainAlias(tracedUnit, bareId);
+              this._ensureNpmAlias(tracedUnit, bareId);
             }
           })
           .catch(err => {

src/package-reader.js

@@ -54,6 +54,13 @@ export default class PackageReader {
 
         let fullResource = resParts.join('/');
 
+        if (ext(fullResource) === '.js') fullResource = fullResource.slice(-3);
+        const replacement = this.browserReplacement['./' + fullResource];
+        if (replacement) {
+           // replacement is always local, remove leading ./
+          fullResource = replacement.slice(2);
+        }
+
         return this._nodejsLoad(fullResource).then(
           filePath => this._readFile(filePath),
           () => {