Use browser-resolve to ignore fs inlining (#523)

src/visitors/fs.js

@@ -20,7 +20,13 @@ module.exports = {
   },
 
   CallExpression(path, asset) {
-    if (referencesImport(path, 'fs', 'readFileSync')) {
+    // See https://github.com/defunctzombie/node-browser-resolve#skip
+    let ignore =
+      asset.package &&
+      asset.package.browser &&
+      asset.package.browser.fs === false;
+
+    if (!ignore && referencesImport(path, 'fs', 'readFileSync')) {
       let vars = {
         __dirname: Path.dirname(asset.name),
         __filename: asset.basename

test/fs.js

@@ -1,5 +1,5 @@
 const assert = require('assert');
-const {bundle, run} = require('./utils');
+const {bundle, run, assertBundleTree} = require('./utils');
 
 describe('fs', function() {
   it('should inline a file as a string', async function() {
@@ -52,4 +52,22 @@ describe('fs', function() {
     let output = run(b);
     assert.equal(output, 'hello');
   });
+
+  it('should not evaluate fs calls when package.browser.fs is false', async function() {
+    let b = await bundle(
+      __dirname + '/integration/resolve-entries/ignore-fs.js'
+    );
+
+    assertBundleTree(b, {
+      name: 'ignore-fs.js',
+      // empty.js is generated by require('fs'), it gets mocked with an empty module
+      assets: ['empty.js', 'ignore-fs.js', 'index.js'],
+      childBundles: []
+    });
+
+    let output = run(b);
+
+    assert.equal(typeof output.test, 'function');
+    assert.equal(output.test(), 'test-pkg-ignore-fs-ok');
+  });
 });

test/integration/resolve-entries/ignore-fs.js

@@ -0,0 +1,5 @@
+import file from './pkg-ignore-fs'
+
+export function test() {
+  return file()
+}

test/integration/resolve-entries/pkg-ignore-fs/index.js

@@ -0,0 +1,9 @@
+export default () => {
+  try {
+    // We expect browser-resolve to replace fs with an empty module, so readFileSync will be undefined
+    return require('fs').readFileSync(__dirname + '/package.json')
+  }
+  catch(_) {
+    return 'test-pkg-ignore-fs-ok'
+  }
+}

test/integration/resolve-entries/pkg-ignore-fs/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "pkg-ignore-fs",
+  "main": "index.js",
+  "browser": {
+    "fs": false
+  }
+}