more nuanced check for wrapping (rollup#53)

src/index.js

@@ -101,7 +101,7 @@ export default function commonjs ( options = {} ) {
 
 			let scope = attachScopes( ast, 'scope' );
 			let uses = { module: false, exports: false, global: false };
-
+			let usesRequire = false;
 			let namedExports = {};
 			if ( customNamedExports[ id ] ) {
 				customNamedExports[ id ].forEach( name => namedExports[ name ] = true );
@@ -145,7 +145,13 @@ export default function commonjs ( options = {} ) {
 					}
 
 					if ( node.type === 'Identifier' ) {
-						if ( ( node.name in uses && !uses[ node.name ] ) && isReference( node, parent ) && !scope.contains( node.name ) ) uses[ node.name ] = true;
+						if ( ( node.name in uses && !uses[ node.name ] ) && isReference( node, parent ) && !scope.contains( node.name ) ) {
+							if (parent && (parent.operator === 'typeof' || parent.type === 'ConditionalExpression')) {
+								return;
+							} else {
+								uses[ node.name ] = true;
+							}
+						}
 						return;
 					}
 
@@ -158,7 +164,7 @@ export default function commonjs ( options = {} ) {
 					if ( node.type !== 'CallExpression' ) return;
 					if ( node.callee.name !== 'require' || scope.contains( 'require' ) ) return;
 					if ( node.arguments.length !== 1 || node.arguments[0].type !== 'Literal' ) return; // TODO handle these weird cases?
-
+					usesRequire = true;
 					const source = node.arguments[0].value;
 
 					let existing = required[ source ];
@@ -187,8 +193,11 @@ export default function commonjs ( options = {} ) {
 			});
 
 			const sources = Object.keys( required );
+			if (options.ignoreGlobal) {
+				uses.global = false;
+			}
 
-			if ( !sources.length && !uses.module && !uses.exports && !uses.global ) {
+			if ( !sources.length && !uses.module && !uses.exports && !uses.global && !usesRequire) {
 				if ( Object.keys( namedExports ).length ) {
 					throw new Error( `Custom named exports were specified for ${id} but it does not appear to be a CommonJS module` );
 				}

test/samples/references-require/encoder.js

@@ -0,0 +1,10 @@
+var _foo;
+(function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
+(function (global){
+module.exports = function (data) {
+  return global.encodeURIComponent(data);
+};
+_foo = module.exports;
+}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
+},{}]},{},[1]);
+export default _foo;

test/samples/references-require/main.js

@@ -0,0 +1,5 @@
+import encoder from './encoder';
+
+export function encode(data) {
+  return encoder(data);
+}

test/test.js

@@ -254,4 +254,24 @@ describe( 'rollup-plugin-commonjs', () => {
 			assert.equal( global.setImmediate, mod.immediate, generated.code );
 		});
 	});
+
+	it( 'can handle references to `require`', () => {
+		return rollup({
+			entry: 'samples/references-require/main.js',
+			plugins: [ commonjs() ]
+		}).then( bundle => {
+			const generated = bundle.generate({
+				format: 'cjs'
+			});
+			var exp = {};
+			let mod = {
+				exports: exp
+			};
+
+			const fn = new Function ( 'module', 'exports', generated.code );
+			fn( mod, exp );
+
+			assert.equal( exp.encode('///'), '%2F%2F%2F', generated.code );
+		});
+	});
 });