fix typeof require === "function" && require (#77, #83)

Author: Rich-Harris

src/helpers.js

@@ -3,6 +3,10 @@ export const HELPERS_ID = '\0commonjsHelpers';
 export const HELPERS = `
 export var commonjsGlobal = typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {};
 
+export function commonjsRequire () {
+	throw new Error('Dynamic requires are not currently supported by rollup-plugin-commonjs');
+}
+
 export function unwrapExports (x) {
 	return x && x.__esModule ? x['default'] : x;
 }

src/transform.js

@@ -59,7 +59,7 @@ export default function transform ( code, id, isEntry, ignoreGlobal, customNamed
 	let uid = 0;
 
 	let scope = attachScopes( ast, 'scope' );
-	const uses = { module: false, exports: false, global: false };
+	const uses = { module: false, exports: false, global: false, require: false };
 
 	let lexicalDepth = 0;
 	let programDepth = 0;
@@ -126,16 +126,6 @@ export default function transform ( code, id, isEntry, ignoreGlobal, customNamed
 				return;
 			}
 
-			// To allow consumption of UMD modules, transform `typeof require` to `'function'`
-			if ( node.type === 'UnaryExpression' && node.operator === 'typeof' && node.argument.type === 'Identifier' ) {
-				const name = node.argument.name;
-
-				if ( name === 'require' && !scope.contains( name ) ) {
-					magicString.overwrite( node.start, node.end, `'function'` );
-					return;
-				}
-			}
-
 			if ( node.type === 'Identifier' ) {
 				if ( isReference( node, parent ) && !scope.contains( node.name ) ) {
 					if ( node.name in uses ) {
@@ -144,6 +134,10 @@ export default function transform ( code, id, isEntry, ignoreGlobal, customNamed
 							magicString.overwrite( node.start, node.end, `${HELPERS_NAME}.commonjsGlobal`, true );
 						}
 
+						if ( node.name === 'require' ) {
+							magicString.overwrite( node.start, node.end, `${HELPERS_NAME}.commonjsRequire`, true );
+						}
+
 						// if module or exports are used outside the context of an assignment
 						// expression, we need to wrap the module
 						if ( node.name === 'module' || node.name === 'exports' ) {
@@ -189,6 +183,8 @@ export default function transform ( code, id, isEntry, ignoreGlobal, customNamed
 				// is a bare import, e.g. `require('foo');`
 				magicString.remove( parent.start, parent.end );
 			}
+
+			node.callee._skip = true;
 		},
 
 		leave ( node ) {

test/function/typeof-require/foo.js

@@ -0,0 +1,5 @@
+if ( typeof require === 'function' && require ) {
+	module.exports = 1;
+} else {
+	module.exports = 2;
+}

test/function/typeof-require/main.js

@@ -0,0 +1,3 @@
+import foo from './foo.js';
+
+assert.equal( foo, 1 );