Make transform stateless

package.json

@@ -3,20 +3,18 @@
   "version": "2.2.1",
   "description": "Convert CommonJS modules to ES2015",
   "devDependencies": {
-    "babel-preset-es2015": "^6.3.13",
-    "babel-preset-es2015-rollup": "^1.0.0",
-    "babel-register": "^6.3.13",
-    "eslint": "^1.7.3",
-    "mocha": "^2.3.3",
-    "rollup": "^0.25.8",
-    "rollup-plugin-babel": "^2.2.0",
-    "rollup-plugin-node-resolve": "^1.1.0",
-    "source-map": "^0.5.3"
+    "buble": "^0.10.6",
+    "eslint": "^2.11.1",
+    "mocha": "^2.5.3",
+    "rollup": "^0.26.7",
+    "rollup-plugin-buble": "^0.10.0",
+    "rollup-plugin-node-resolve": "^1.6.0",
+    "source-map": "^0.5.6"
   },
   "main": "dist/rollup-plugin-commonjs.cjs.js",
   "jsnext:main": "dist/rollup-plugin-commonjs.es6.js",
   "scripts": {
-    "test": "mocha --compilers js:babel-register",
+    "test": "mocha --compilers js:buble/register",
     "pretest": "npm run build",
     "build": "rm -rf dist/* && rollup -c -f cjs -o dist/rollup-plugin-commonjs.cjs.js && rollup -c -f es6 -o dist/rollup-plugin-commonjs.es6.js",
     "prepublish": "npm test"
@@ -27,11 +25,11 @@
     "README.md"
   ],
   "dependencies": {
-    "acorn": "^2.4.0",
-    "estree-walker": "^0.2.0",
-    "magic-string": "^0.10.0",
-    "resolve": "^1.1.6",
-    "rollup-pluginutils": "^1.2.0"
+    "acorn": "^3.1.0",
+    "estree-walker": "^0.2.1",
+    "magic-string": "^0.15.0",
+    "resolve": "^1.1.7",
+    "rollup-pluginutils": "^1.5.0"
   },
   "repository": {
     "type": "git",

rollup.config.js

@@ -1,9 +1,9 @@
-import babel from 'rollup-plugin-babel';
+import buble from 'rollup-plugin-buble';
 
 var external = Object.keys( require( './package.json' ).dependencies ).concat([ 'fs', 'path' ]);
 
 export default {
 	entry: 'src/index.js',
-	plugins: [ babel() ],
+	plugins: [ buble() ],
 	external: external
 };

src/index.js

@@ -37,13 +37,27 @@ function getCandidates ( resolved, extensions ) {
 	);
 }
 
+function deconflict ( identifier, code ) {
+	let i = 1;
+	let deconflicted = identifier;
+
+	while ( ~code.indexOf( deconflicted ) ) deconflicted = `${identifier}_${i++}`;
+	return deconflicted;
+}
+
+const HELPERS_ID = '\0commonjsHelpers';
+const HELPERS = `
+export var commonjsGlobal = typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {}
+
+export function createCommonjsModule(fn, module) {
+	return module = { exports: {} }, fn(module, module.exports), module.exports;
+}`;
+
 export default function commonjs ( options = {} ) {
 	const extensions = options.extensions || ['.js'];
 	const filter = createFilter( options.include, options.exclude );
 	const ignoreGlobal = options.ignoreGlobal;
 	const firstpass = ignoreGlobal ? firstpassNoGlobal : firstpassGlobal;
-	let bundleUsesGlobal = false;
-	let bundleRequiresWrappers = false;
 
 	const sourceMap = options.sourceMap !== false;
 
@@ -64,6 +78,8 @@ export default function commonjs ( options = {} ) {
 
 	return {
 		resolveId ( importee, importer ) {
+			if ( importee === HELPERS_ID ) return importee;
+
 			if ( importee[0] !== '.' ) return; // not our problem
 
 			const resolved = resolve( dirname( importer ), importee );
@@ -77,6 +93,10 @@ export default function commonjs ( options = {} ) {
 			}
 		},
 
+		load ( id ) {
+			if ( id === HELPERS_ID ) return HELPERS;
+		},
+
 		transform ( code, id ) {
 			if ( !filter( id ) ) return null;
 			if ( extensions.indexOf( extname( id ) ) === -1 ) return null;
@@ -109,6 +129,8 @@ export default function commonjs ( options = {} ) {
 
 			let scopeDepth = 0;
 
+			const HELPERS_NAME = deconflict( 'commonjsHelpers', code );
+
 			walk( ast, {
 				enter ( node, parent ) {
 					if ( node.scope ) scope = node.scope;
@@ -145,13 +167,16 @@ 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 ) ) {
+							uses[ node.name ] = true;
+							if ( node.name === 'global' ) magicString.overwrite( node.start, node.end, `${HELPERS_NAME}.commonjsGlobal` );
+						}
 						return;
 					}
 
 					if ( node.type === 'ThisExpression' && scopeDepth === 0 && !ignoreGlobal ) {
 						uses.global = true;
-						magicString.overwrite( node.start, node.end, `__commonjs_global`, true );
+						magicString.overwrite( node.start, node.end, `${HELPERS_NAME}.commonjsGlobal`, true );
 						return;
 					}
 
@@ -195,20 +220,18 @@ export default function commonjs ( options = {} ) {
 				return null; // not a CommonJS module
 			}
 
-			bundleRequiresWrappers = true;
-
 			const name = getName( id );
 
-			const importBlock = sources.length ?
+			const importBlock = [ `import * as ${HELPERS_NAME} from '${HELPERS_ID}';` ].concat(
 				sources.map( source => {
 					const { name, importsDefault } = required[ source ];
 					return `import ${importsDefault ? `${name} from ` : ``}'${source}';`;
-				}).join( '\n' ) :
-				'';
+				})
+			).join( '\n' );
 
-			const args = `module${uses.exports || uses.global ? ', exports' : ''}${uses.global ? ', global' : ''}`;
+			const args = `module${uses.exports ? ', exports' : ''}`;
 
-			const intro = `\n\nvar ${name} = __commonjs(function (${args}) {\n`;
+			const intro = `\n\nvar ${name} = ${HELPERS_NAME}.createCommonjsModule(function (${args}) {\n`;
 			let outro = `\n});\n\nexport default (${name} && typeof ${name} === 'object' && 'default' in ${name} ? ${name}['default'] : ${name});\n`;
 
 			outro += Object.keys( namedExports )
@@ -224,23 +247,7 @@ export default function commonjs ( options = {} ) {
 			code = magicString.toString();
 			const map = sourceMap ? magicString.generateMap() : null;
 
-			if ( uses.global ) bundleUsesGlobal = true;
-
 			return { code, map };
-		},
-
-		intro () {
-			var intros = [];
-
-			if ( bundleUsesGlobal ) {
-				intros.push( `var __commonjs_global = typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {}` );
-			}
-
-			if ( bundleRequiresWrappers ) {
-				intros.push( `function __commonjs(fn, module) { return module = { exports: {} }, fn(module, module.exports${bundleUsesGlobal ? ', __commonjs_global' : ''}), module.exports; }\n` );
-			}
-
-			return intros.join( '\n' );
 		}
 	};
 }

test/samples/__esModule/main.js

@@ -1,2 +1,5 @@
-exports.__esModule = true;
-exports.answer = 42;
+import * as x from './answer';
+
+assert.ok( 'answer' in x );
+assert.ok( 'default' in x ); // TODO is this right?
+assert.ok( !( '__esModule' in x ) );

test/samples/deconflict-helpers/main.js

@@ -0,0 +1,2 @@
+var commonjsHelpers = { commonjsGlobal: 'nope' };
+module.exports = global;

test/test.js

@@ -1,9 +1,9 @@
-import * as path from 'path';
-import * as assert from 'assert';
-import { SourceMapConsumer } from 'source-map';
-import { rollup } from 'rollup';
-import nodeResolve from 'rollup-plugin-node-resolve';
-import commonjs from '..';
+const path = require( 'path' );
+const assert = require( 'assert' );
+const { SourceMapConsumer } = require( 'source-map' );
+const { rollup } = require( 'rollup' );
+const nodeResolve = require( 'rollup-plugin-node-resolve' );
+const commonjs = require( '..' );
 
 process.chdir( __dirname );
 
@@ -20,6 +20,27 @@ function executeBundle ( bundle ) {
 	return module;
 }
 
+function getLocation ( source, charIndex ) {
+	var lines = source.split( '\n' );
+	var len = lines.length;
+
+	var lineStart = 0;
+	var i;
+
+	for ( i = 0; i < len; i += 1 ) {
+		var line = lines[i];
+		var lineEnd =  lineStart + line.length + 1; // +1 for newline
+
+		if ( lineEnd > charIndex ) {
+			return { line: i + 1, column: charIndex - lineStart };
+		}
+
+		lineStart = lineEnd;
+	}
+
+	throw new Error( 'Could not determine location of character' );
+}
+
 describe( 'rollup-plugin-commonjs', () => {
 	it( 'converts a basic CommonJS module', () => {
 		return rollup({
@@ -61,12 +82,14 @@ describe( 'rollup-plugin-commonjs', () => {
 
 			const smc = new SourceMapConsumer( generated.map );
 
-			let loc = smc.originalPositionFor({ line: 5, column: 17 }); // 42
+			let generatedLoc = getLocation( generated.code, generated.code.indexOf( '42' ) );
+			let loc = smc.originalPositionFor( generatedLoc ); // 42
 			assert.equal( loc.source, 'samples/sourcemap/foo.js' );
 			assert.equal( loc.line, 1 );
 			assert.equal( loc.column, 15 );
 
-			loc = smc.originalPositionFor({ line: 9, column: 8 }); // log
+			generatedLoc = getLocation( generated.code, generated.code.indexOf( 'log' ) );
+			loc = smc.originalPositionFor( generatedLoc ); // log
 			assert.equal( loc.source, 'samples/sourcemap/main.js' );
 			assert.equal( loc.line, 2 );
 			assert.equal( loc.column, 8 );
@@ -176,18 +199,7 @@ describe( 'rollup-plugin-commonjs', () => {
 		return rollup({
 			entry: 'samples/__esModule/main.js',
 			plugins: [ commonjs() ]
-		}).then( bundle => {
-			const generated = bundle.generate({
-				format: 'cjs'
-			});
-
-			const fn = new Function ( 'module', 'exports', generated.code );
-			let module = { exports: {} };
-
-			fn( module, module.exports );
-
-			assert.ok( !module.exports.__esModule );
-		});
+		}).then( executeBundle );
 	});
 
 	it( 'allows named exports to be added explicitly via config', () => {
@@ -254,4 +266,13 @@ describe( 'rollup-plugin-commonjs', () => {
 			assert.equal( global.setImmediate, mod.immediate, generated.code );
 		});
 	});
+
+	it( 'deconflicts helper name', () => {
+		return rollup({
+			entry: 'samples/deconflict-helpers/main.js',
+			plugins: [ commonjs() ]
+		}).then( executeBundle ).then( module => {
+			assert.notEqual( module.exports, 'nope' );
+		});
+	})
 });