Add support for es2015 field

README.md

@@ -25,6 +25,9 @@ export default {
   name: 'MyModule',
   plugins: [
     resolve({
+      // use "es2015" field for ES6 module if possible
+      es2015: true, // Default: false
+
       // use "module" field for ES6 module if possible
       module: true, // Default: true
 

src/index.js

@@ -40,6 +40,7 @@ function cachedIsFile (file, cb) {
 const resolveIdAsync = (file, opts) => new Promise((fulfil, reject) => resolveId(file, opts, (err, contents) => err ? reject(err) : fulfil(contents)));
 
 export default function nodeResolve ( options = {} ) {
+	const useEs2015 = options.es2015 === true;
 	const useModule = options.module !== false;
 	const useMain = options.main !== false;
 	const useJsnext = options.jsnext === true;
@@ -59,8 +60,8 @@ export default function nodeResolve ( options = {} ) {
 		throw new Error( 'options.skip is no longer supported — you should use the main Rollup `external` option instead' );
 	}
 
-	if ( !useModule && !useMain && !useJsnext ) {
-		throw new Error( `At least one of options.module, options.main or options.jsnext must be true` );
+	if ( !useEs2015 && !useModule && !useMain && !useJsnext ) {
+		throw new Error( `At least one of options.es2015, options.module, options.main or options.jsnext must be true` );
 	}
 
 	let preserveSymlinks;
@@ -135,11 +136,13 @@ export default function nodeResolve ( options = {} ) {
 
 					if (options.browser && typeof pkg[ 'browser' ] === 'string') {
 						pkg[ 'main' ] = pkg[ 'browser' ];
+					} else if ( useEs2015 && pkg[ 'es2015' ] ) {
+						pkg[ 'main' ] = pkg[ 'es2015' ];
 					} else if ( useModule && pkg[ 'module' ] ) {
 						pkg[ 'main' ] = pkg[ 'module' ];
 					} else if ( useJsnext && pkg[ 'jsnext:main' ] ) {
 						pkg[ 'main' ] = pkg[ 'jsnext:main' ];
-					} else if ( ( useJsnext || useModule ) && !useMain ) {
+					} else if ( ( useEs2015 || useJsnext || useModule ) && !useMain ) {
 						disregardResult = true;
 					}
 					return pkg;

test/samples/es2015/main.js

@@ -0,0 +1,3 @@
+import es2015 from 'es2015';
+
+export default es2015; // ES2015

test/samples/prefer-es2015/main.js

@@ -0,0 +1,3 @@
+import entry from 'entries';
+
+export default entry;

test/test.js

@@ -47,6 +47,17 @@ describe( 'rollup-plugin-node-resolve', function () {
 		});
 	});
 
+	it( 'finds a module with es2015', function () {
+		return rollup.rollup({
+			input: 'samples/es2015/main.js',
+			plugins: [
+				nodeResolve({ es2015: true })
+			]
+		}).then( executeBundle ).then( module => {
+			assert.equal( module.exports, 'ES2015' );
+		});
+	});
+
 	it( 'finds and converts a basic CommonJS module', function () {
 		return rollup.rollup({
 			input: 'samples/commonjs/main.js',
@@ -445,6 +456,17 @@ describe( 'rollup-plugin-node-resolve', function () {
 		});
 	});
 
+	it( 'prefers es2015 field over module, jsnext:main and main', () => {
+		return rollup.rollup({
+			input: 'samples/prefer-es2015/main.js',
+			plugins: [
+				nodeResolve({ es2015: true, jsnext: true, preferBuiltins: false })
+			]
+		}).then( executeBundle ).then( module => {
+			assert.equal( module.exports, 'ES2015-ENTRY' );
+		});
+	});
+
 	it('finds and uses an .mjs module', function () {
 		return rollup.rollup({
 			input: 'samples/module-mjs/main.js',