fix #455: "module.require" forwards to "require"

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+* `module.require` forwards to the host's `require` ([#455](https://github.com/evanw/esbuild/issues/455))
+
+    Some packages such as [apollo-server](https://github.com/apollographql/apollo-server) use `module.require` with the intent of bypassing the bundler's `require` and calling the underlying function from `node` instead. Unfortunately that doesn't work because esbuild recognizes CommonJS module syntax and `module` has special meaning for CommonJS modules.
+
+    To get this package to work, `module.require` now forwards to `require` in the host environment. This will be the underlying `require` function in node and will be `window.require` in the browser, which will crash unless you provide a polyfill yourself.
+
 ## 0.7.15
 
 * Lower `export * as` syntax for ES2019 and below

internal/bundler/snapshots/snapshots_default.txt

@@ -1051,7 +1051,7 @@ console.log(shared_default);
 ================================================================================
 TestMinifiedBundleCommonJS
 ---------- /out.js ----------
-var n=e(r=>{r.foo=function(){return 123}});var u=e((j,t)=>{t.exports={test:!0}});const{foo:c}=n();console.log(c(),u());
+var t=r(n=>{n.foo=function(){return 123}});var s=r((l,u)=>{u.exports={test:!0}});const{foo:f}=t();console.log(f(),s());
 
 ================================================================================
 TestMinifiedBundleES6

internal/bundler/snapshots/snapshots_importstar.txt

@@ -113,11 +113,11 @@ module.exports = require_entry();
 TestExportSelfCommonJSMinified
 ---------- /out.js ----------
 // /entry.js
-var e = n((t, r) => {
-  r.exports = {foo: 123};
-  console.log(e());
+var r = s((c, l) => {
+  l.exports = {foo: 123};
+  console.log(r());
 });
-module.exports = e();
+module.exports = r();
 
 ================================================================================
 TestExportSelfES6

internal/bundler/snapshots/snapshots_ts.txt

@@ -270,7 +270,7 @@ console.log(a, b, c, d, e, real);
 ================================================================================
 TestTSMinifiedBundleCommonJS
 ---------- /out.js ----------
-var n=e(r=>{r.foo=function(){return 123}});var u=e((j,t)=>{t.exports={test:!0}});const{foo:c}=n();console.log(c(),u());
+var t=r(n=>{n.foo=function(){return 123}});var s=r((l,u)=>{u.exports={test:!0}});const{foo:f}=t();console.log(f(),s());
 
 ================================================================================
 TestTSMinifiedBundleES6

internal/runtime/runtime.go

@@ -46,10 +46,14 @@ func code(isES6 bool) string {
 			return target
 		}
 
+		// Some libraries such as "apollo-server" use "module.require" to bypass
+		// the bundler and get at the underlying "require" function from node
+		export var __require = path => require(path)
+
 		// Wraps a CommonJS closure and returns a require() function
 		export var __commonJS = (callback, module) => () => {
 			if (!module) {
-				module = {exports: {}}
+				module = {exports: {}, require: __require}
 				callback(module.exports, module)
 			}
 			return module.exports

scripts/end-to-end-tests.js

@@ -111,6 +111,15 @@
     }),
   )
 
+  // Test CommonJS "module.require" bypassing the bundler's require
+  tests.push(
+    test(['--bundle', 'in.js', '--outfile=out.js', '--format=cjs'], {
+      'in.js': `export {foo} from './foo'`,
+      'foo.js': `exports.foo = module.require('fs').exists`,
+      'node.js': `if (require('./out').foo !== require('fs').exists) throw 'fail'`,
+    }),
+  )
+
   // Test internal CommonJS export
   tests.push(
     test(['--bundle', 'in.js', '--outfile=node.js'], {