Merge pull request #182 from esnext/es6-class-support

Add support for exporting ES6 classes.

Author: eventualbuddha

lib/exports.js

@@ -51,6 +51,8 @@ ExportDeclarationList.prototype.declarationForNode = function(node) {
  return new VariableExportDeclaration(this.module, node);
  } else if (n.FunctionDeclaration.check(node.declaration)) {
  return new FunctionExportDeclaration(this.module, node);
+ } else if (n.ClassDeclaration.check(node.declaration)) {
+ return new ClassExportDeclaration(this.module, node);
  } else if (n.ExportBatchSpecifier.check(node.specifiers[0])) {
  throw new Error(
  '`export *` found at ' + sourcePosition(this.module, node) +
@@ -200,6 +202,31 @@ memo(VariableExportDeclaration.prototype, 'specifiers', /** @this VariableExport
  });
 });
 
+/**
+ * Represents an export declaration of the form:
+ *
+ * export class Foo {}
+ *
+ * @constructor
+ * @extends ExportDeclaration
+ * @param {Module} mod
+ * @param {AST.ExportDeclaration} node
+ */
+function ClassExportDeclaration(mod, node) {
+ ExportDeclaration.call(this, mod, node);
+}
+extend(ClassExportDeclaration, ExportDeclaration);
+
+/**
+ * Gets the list of export specifiers for this declaration.
+ *
+ * @type {ExportSpecifier[]}
+ * @name ClassExportDeclaration#specifiers
+ */
+memo(ClassExportDeclaration.prototype, 'specifiers', /** @this ClassExportDeclaration */function() {
+ return [new ExportSpecifier(this, this.node.declaration)];
+});
+
 /**
  * Represents an export declaration of the form:
  *

lib/formatters/bundle_formatter.js

@@ -329,6 +329,14 @@ BundleFormatter.prototype.processExportDeclaration = function(mod, nodePath) {
  // transform the function
  this.processFunctionDeclaration(mod, nodePath.get('declaration'))
  );
+ } else if (n.ClassDeclaration.check(node.declaration)) {
+ return Replacement.swaps(
+ // drop `export`
+ nodePath, node.declaration
+ ).and(
+ // transform the class
+ this.processClassDeclaration(mod, nodePath.get('declaration'))
+ );
  } else if (n.VariableDeclaration.check(node.declaration)) {
  return Replacement.swaps(
  // drop `export`
@@ -394,6 +402,28 @@ BundleFormatter.prototype.processFunctionDeclaration = function(mod, nodePath) {
  );
 };
 
+/**
+ * Rename the top-level class declaration to a unique name.
+ *
+ * ```js
+ * class Foo {}
+ * ```
+ *
+ * Becomes e.g.
+ *
+ * ```js
+ * class mod$$Foo {}
+ * ```
+ *
+ * @override
+ */
+BundleFormatter.prototype.processClassDeclaration = function(mod, nodePath) {
+ return Replacement.swaps(
+ nodePath.get('id'),
+ this.reference(mod, nodePath.node.id)
+ );
+};
+
 /**
  * Since import declarations only control how we rewrite references we can just
  * remove them -- they don't turn into any actual statements.

package.json

@@ -46,6 +46,7 @@
  },
  "devDependencies": {
  "browserify": "^5.12.1",
+ "es6-class": "^0.9.1",
  "example-runner": "^0.1.0",
  "fake-fs": "^0.4.0",
  "mocha": "^1.20.1",
@@ -55,4 +56,4 @@
  "fs": "./lib/browser/fs.js",
  "./lib/index.js": "./lib/browser/index.js"
  }
-}
+}

test/examples/export-class-expression/exporter.js

@@ -0,0 +1,3 @@
+/* jshint esnext:true */
+
+export default class {};

test/examples/export-class-expression/importer.js

@@ -0,0 +1,5 @@
+/* jshint esnext:true */
+
+import Foo from './exporter';
+
+assert.strictEqual(new Foo().constructor, Foo);

test/examples/export-class/exporter.js

@@ -0,0 +1,3 @@
+/* jshint esnext:true */
+
+export class Foo {}

test/examples/export-class/importer.js

@@ -0,0 +1,5 @@
+/* jshint esnext:true */
+
+import { Foo } from './exporter';
+
+assert.strictEqual(new Foo().constructor, Foo);

test/examples/export-default-class/exporter.js

@@ -0,0 +1,8 @@
+/* jshint esnext:true */
+
+export default class Point {
+ constructor(x, y) {
+ this.x = x;
+ this.y = y;
+ }
+}

test/examples/export-default-class/importer.js

@@ -0,0 +1,6 @@
+/* jshint esnext:true */
+
+import Point from './exporter';
+
+assert.strictEqual(new Point(1, 2).x, 1);
+assert.strictEqual(new Point(1, 2).y, 2);

test/runner.js

@@ -6,6 +6,7 @@ var fs = require('fs');
 var Path = require('path');
 var vm = require('vm');
 var assert = require('assert');
+var es6class = require('es6-class');
 
 var modules = require('../lib');
 var utils = require('../lib/utils');
@@ -183,7 +184,7 @@ function requireTestFile(path, relativeTo, assert) {
  };
 
  // Hack to work around an issue where vm does not set `this` to the context.
- code = '(function(){' + code + '\n}).call(global);';
+ code = '(function(){' + es6class.compile(code).code + '\n}).call(global);';
  vm.runInNewContext(code, testFileGlobal, path);
 
  testFileCache[path] = mod.exports;