Fix pkg.browser mappings issue by specifying a value of false (#183)

* Fix pkg.browser mappings issue by specifying a value of `false`

* Add tests for #183

src/index.js

@@ -82,6 +82,7 @@ export default function nodeResolve ( options = {} ) {
 
 			const basedir = importer ? dirname( importer ) : process.cwd();
 
+			// https://github.com/defunctzombie/package-browser-field-spec
 			if (options.browser && browserMapCache[importer]) {
 				const resolvedImportee = resolve( basedir, importee );
 				const browser = browserMapCache[importer];
@@ -157,16 +158,19 @@ export default function nodeResolve ( options = {} ) {
 				importee,
 				Object.assign( resolveOptions, customResolveOptions )
 			)
-				.catch(() => false)
 				.then(resolved => {
-					if (options.browser && packageBrowserField) {
-						if (packageBrowserField[ resolved ]) {
+					if ( resolved && options.browser && packageBrowserField ) {
+						if ( packageBrowserField.hasOwnProperty(resolved) ) {
+							if (!packageBrowserField[resolved]) {
+								browserMapCache[resolved] = packageBrowserField;
+								return ES6_BROWSER_EMPTY;
+							}
 							resolved = packageBrowserField[ resolved ];
 						}
 						browserMapCache[resolved] = packageBrowserField;
 					}
 
-					if ( !disregardResult && resolved !== false ) {
+					if ( !disregardResult ) {
 						if ( !preserveSymlinks && resolved && fs.existsSync( resolved ) ) {
 							resolved = fs.realpathSync( resolved );
 						}
@@ -190,9 +194,10 @@ export default function nodeResolve ( options = {} ) {
 					if ( resolved && options.modulesOnly ) {
 						return readFileAsync( resolved, 'utf-8').then(code => isModule( code ) ? resolved : null);
 					} else {
-						return resolved === false ? null : resolved;
+						return resolved;
 					}
-				});
+				})
+				.catch(() => null);
 		}
 	};
 }

test/samples/browser-object-with-false/main.js

@@ -0,0 +1,15 @@
+import Client from 'isomorphic-object-with-false';
+import HTTPTracker from 'isomorphic-object-with-false/lib/client/http-tracker';
+import ES6_BROWSER_EMPTY from '../../../src/empty';
+import HTTPTrackerWithSubPath from 'isomorphic-object-with-false/lib/subpath/foo';
+
+// do some assert
+
+assert.deepEqual(new Client('ws:'), { name: 'websocket-tracker' })
+assert.deepEqual(new Client('http:'), { name: 'NULL' })
+assert.equal(HTTPTracker, ES6_BROWSER_EMPTY);
+assert.equal(HTTPTrackerWithSubPath, ES6_BROWSER_EMPTY);
+
+
+// expose
+export default "ok"

test/test.js

@@ -657,4 +657,17 @@ describe( 'rollup-plugin-node-resolve', function () {
 		}).then(executeBundle)
 			.then(({exports}) => exports.then(result => assert.equal(result.default, 42)));
 	});
+
+	it( 'pkg.browser with mapping to prevent bundle by specifying a value of false', () => {
+		return rollup.rollup({
+			input: 'samples/browser-object-with-false/main.js',
+			plugins: [
+				nodeResolve({ browser: true }),
+				commonjs()
+			]
+		}).then( executeBundle ).then( module => {
+			assert.equal( module.exports, 'ok' );
+		});
+	});
+
 });