Close PR #573: Added support for babel config under package.json/ava key

Fixes #448

Author: Stephen Sorensen

api.js

@@ -187,7 +187,7 @@ Api.prototype.run = function (files) {
 				uniqueTempDir();
 
 			self.options.cacheDir = cacheDir;
-			self.precompiler = new CachingPrecompiler(cacheDir);
+			self.precompiler = new CachingPrecompiler(cacheDir, self.options.babelConfig);
 			self.fileCount = files.length;
 			self.base = path.relative('.', commonPathPrefix(files)) + path.sep;
 

cli.js

@@ -35,7 +35,11 @@ var Api = require('./api');
 // Bluebird specific
 Promise.longStackTraces();
 
-var conf = pkgConf.sync('ava');
+var conf = pkgConf.sync('ava', {
+	defaults: {
+		babel: 'default'
+	}
+});
 
 var cli = meow([
 	'Usage',
@@ -102,7 +106,8 @@ var api = new Api({
 	require: arrify(cli.flags.require),
 	cacheEnabled: cli.flags.cache !== false,
 	explicitTitles: cli.flags.watch,
-	match: arrify(cli.flags.match)
+	match: arrify(cli.flags.match),
+	babelConfig: conf.babel
 });
 
 var reporter;

lib/caching-precompiler.js

@@ -3,20 +3,21 @@ var path = require('path');
 var cachingTransform = require('caching-transform');
 var md5Hex = require('md5-hex');
 var stripBom = require('strip-bom');
+var objectAssign = require('object-assign');
 
 module.exports = CachingPrecompiler;
 
-function CachingPrecompiler(cacheDir) {
+function CachingPrecompiler(cacheDir, babelConfig) {
 	if (!(this instanceof CachingPrecompiler)) {
 		throw new TypeError('Class constructor CachingPrecompiler cannot be invoked without \'new\'');
 	}
 
 	this.cacheDir = cacheDir;
 	this.filenameToHash = {};
-	this.transform = this._createTransform();
+	this.transform = this._createTransform(babelConfig);
 }
 
-CachingPrecompiler.prototype._factory = function (cacheDir) {
+CachingPrecompiler.prototype._factory = function (babelConfig, cacheDir) {
 	// This factory method is only called once per process, and only as needed, to defer loading expensive dependencies.
 	var babel = require('babel-core');
 	var convertSourceMap = require('convert-source-map');
@@ -30,15 +31,27 @@ CachingPrecompiler.prototype._factory = function (cacheDir) {
 		// Extract existing source maps from the code.
 		var sourceMap = convertSourceMap.fromSource(code) || convertSourceMap.fromMapFileSource(code, path.dirname(filename));
 
-		return {
-			presets: [presetStage2, presetES2015],
-			plugins: [powerAssert, transformRuntime],
+		var options = {babelrc: false};
+
+		if (!babelConfig || babelConfig === 'default') {
+			objectAssign(options, {presets: [presetStage2, presetES2015]});
+		} else if (babelConfig === 'inherit') {
+			objectAssign(options, {babelrc: true});
+		} else {
+			objectAssign(options, babelConfig);
+		}
+
+		objectAssign(options, {
+			inputSourceMap: sourceMap && sourceMap.toObject(),
 			filename: filename,
 			sourceMaps: true,
-			ast: false,
-			babelrc: false,
-			inputSourceMap: sourceMap && sourceMap.toObject()
-		};
+			ast: false
+		});
+
+		options.plugins = options.plugins || [];
+		options.plugins.push(powerAssert, transformRuntime);
+
+		return options;
 	}
 
 	return function (code, filename, hash) {
@@ -61,14 +74,15 @@ CachingPrecompiler.prototype._createEspowerPlugin = function (babel) {
 	});
 };
 
-CachingPrecompiler.prototype._createTransform = function () {
+CachingPrecompiler.prototype._createTransform = function (babelConfig) {
 	return cachingTransform({
-		factory: this._factory.bind(this),
+		factory: this._factory.bind(this, babelConfig),
 		cacheDir: this.cacheDir,
 		salt: new Buffer(JSON.stringify({
 			'babel-plugin-espower': require('babel-plugin-espower/package.json').version,
 			'ava': require('../package.json').version,
-			'babel-core': require('babel-core/package.json').version
+			'babel-core': require('babel-core/package.json').version,
+			'babelConfig': babelConfig
 		})),
 		ext: '.js',
 		hash: this._hash.bind(this)

profile.js

@@ -20,7 +20,11 @@ globals.setTimeout = setTimeout.bind(null);
 globals.clearTimeout = clearTimeout.bind(null);
 
 Promise.longStackTraces();
-var conf = pkgConf.sync('ava');
+var conf = pkgConf.sync('ava', {
+	defaults: {
+		babel: 'default'
+	}
+});
 
 // Define a minimal set of options from the main CLI.
 var cli = meow([
@@ -63,7 +67,7 @@ var opts = {
 	require: arrify(cli.flags.require),
 	tty: false,
 	cacheDir: cacheDir,
-	precompiled: new CachingPrecompiler(cacheDir).generateHashForFile(file)
+	precompiled: new CachingPrecompiler(cacheDir, conf.babel).generateHashForFile(file)
 };
 
 var events = new EventEmitter();

readme.md

@@ -154,7 +154,8 @@ All of the CLI options can be configured in the `ava` section of your `package.j
     "tap": true,
     "require": [
       "babel-register"
-    ]
+    ],
+    "babel": "inherit"
   }
 }
 ```
@@ -423,6 +424,61 @@ AVA comes with builtin support for ES2015 through [Babel 6](https://babeljs.io).
 
 AVA includes typings for TypeScript. You have to setup transpilation yourself. When you set `module` to `commonjs` in your `tsconfig.json` file, TypeScript will automatically find the type definitions for AVA. You should set `target` to `es2015` to use Promises and async functions.
 
+### Babel Configuration for Test Scripts
+
+If you want to customize the babel transpiler for test files, you can do so by adding a `"babel"` key to the `ava` section in your `package.json` file.
+
+```json
+{
+	"ava": {
+		 "babel": {
+			 "presets": [
+					"es2015",
+					"stage-0",
+					"react"
+			 ]
+		 }
+	},
+}
+```
+
+In addition to specifying a custom Babel config, you can also use the special `"inherit"` keyword. When you do this, AVA will allow tests to be transpiled using the configuration defined in your `.babelrc` file or in package.json/babel. This way, your test files will be transpiled using the same options as your source files, but you won't have to define the options twice.
+
+```json
+{
+	"babel": {
+		"presets": [
+			"es2015",
+			"stage-0",
+			"react"
+		]
+	},
+	"ava": {
+		"babel": "inherit",
+	},
+}
+```
+
+Note: When configuring Babel for tests manually, the espower and transform-runtime plugins will be
+added for you.
+
+## Default Babel Configuration for Test Scripts
+
+If you don't explicitly configure Babel for your tests using the `"babel"` key in package.json, your tests will be transpiled using AVA's default Babel configuration, which is as follows:
+
+```json
+{
+  "presets": [
+    "es2015",
+    "stage-0",
+  ],
+  "plugins": [
+    "espower",
+    "transform-runtime"
+  ]
+}
+```
+
 #### Transpiling Imported Modules
 
 AVA currently only transpiles the tests you ask it to run. *It will not transpile modules you ```import``` from outside of the test.* While there are valid reasons for taking this approach, it may not be what you expect!

test/api.js

@@ -5,6 +5,7 @@ var rimraf = require('rimraf');
 var fs = require('fs');
 var test = require('tap').test;
 var Api = require('../api');
+var testDoublerPlugin = require('./fixture/babel-plugin-test-doubler');
 
 test('must be called with new', function (t) {
 	t.throws(function () {
@@ -684,3 +685,33 @@ test('verify test count', function (t) {
 		t.is(api.todoCount, 1);
 	});
 });
+
+test('Custom Babel Plugin Support', function (t) {
+	t.plan(1);
+
+	var api = new Api({
+		babelConfig: {
+			presets: ['es2015', 'stage-2'],
+			plugins: [testDoublerPlugin]
+		}
+	});
+
+	api.run([path.join(__dirname, 'fixture/es2015.js')])
+		.then(
+			function () {
+				t.is(api.passCount, 2);
+			},
+			t.threw
+		);
+});
+
+test('Default babel config doesn\'t use .babelrc', function (t) {
+	t.plan(1);
+
+	var api = new Api();
+
+	return api.run([path.join(__dirname, 'fixture/babelrc/test.js')])
+		.then(function () {
+			t.is(api.passCount, 1);
+		});
+});

test/caching-precompiler.js

@@ -3,6 +3,9 @@ var fs = require('fs');
 var path = require('path');
 var test = require('tap').test;
 var uniqueTempDir = require('unique-temp-dir');
+var sinon = require('sinon');
+var babel = require('babel-core');
+var transformRuntime = require('babel-plugin-transform-runtime');
 
 var CachingPrecompiler = require('../lib/caching-precompiler');
 
@@ -18,24 +21,26 @@ function endsWithMap(filename) {
 	return /\.js$/.test(filename);
 }
 
+sinon.spy(babel, 'transform');
+
 test('creation with new', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir);
+	var precompiler = new CachingPrecompiler(tempDir, null);
 	t.is(precompiler.cacheDir, tempDir);
 	t.end();
 });
 
 test('must be called with new', function (t) {
 	t.throws(function () {
 		var cachingPrecompiler = CachingPrecompiler;
-		cachingPrecompiler(uniqueTempDir());
+		cachingPrecompiler(uniqueTempDir(), null);
 	}, {message: 'Class constructor CachingPrecompiler cannot be invoked without \'new\''});
 	t.end();
 });
 
 test('adds files and source maps to the cache directory as needed', function (t) {
 	var tempDir = uniqueTempDir();
-	var precompiler = new CachingPrecompiler(tempDir);
+	var precompiler = new CachingPrecompiler(tempDir, null);
 
 	t.false(fs.existsSync(tempDir), 'cache directory is not created before it is needed');
 
@@ -48,3 +53,67 @@ test('adds files and source maps to the cache directory as needed', function (t)
 	t.is(files.filter(endsWithMap).length, 1, 'one .map file is saved to the cache');
 	t.end();
 });
+
+test('uses default babel options when babelConfig === "default"', function (t) {
+	var tempDir = uniqueTempDir();
+	var precompiler = new CachingPrecompiler(tempDir, 'default');
+	babel.transform.reset();
+
+	precompiler.precompileFile(fixture('es2015.js'));
+
+	t.true(babel.transform.calledOnce);
+	var options = babel.transform.firstCall.args[1];
+
+	t.true('filename' in options);
+	t.true(options.sourceMaps);
+	t.false(options.ast);
+	t.true('inputSourceMap' in options);
+	t.false(options.babelrc);
+	t.true(Array.isArray(options.presets));
+	t.true(Array.isArray(options.plugins));
+	t.end();
+});
+
+test('allows babel config from package.json/babel when babelConfig === "inherit"', function (t) {
+	var tempDir = uniqueTempDir();
+	var precompiler = new CachingPrecompiler(tempDir, 'inherit');
+	babel.transform.reset();
+
+	precompiler.precompileFile(fixture('es2015.js'));
+
+	t.true(babel.transform.calledOnce);
+	var options = babel.transform.firstCall.args[1];
+
+	t.true('filename' in options);
+	t.true(options.sourceMaps);
+	t.false(options.ast);
+	t.true('inputSourceMap' in options);
+	t.true(options.babelrc);
+	t.end();
+});
+
+test('uses babelConfig for babel options when babelConfig is an object', function (t) {
+	var tempDir = uniqueTempDir();
+	var customPlugin = sinon.stub().returns({visitor: {}});
+	var powerAssert = sinon.stub().returns({visitor: {}});
+	var precompiler = new CachingPrecompiler(tempDir, {
+		presets: ['stage-2', 'es2015'],
+		plugins: [customPlugin]
+	});
+	sinon.stub(precompiler, '_createEspowerPlugin').returns(powerAssert);
+	babel.transform.reset();
+
+	precompiler.precompileFile(fixture('es2015.js'));
+
+	t.true(babel.transform.calledOnce);
+	var options = babel.transform.firstCall.args[1];
+
+	t.true('filename' in options);
+	t.true(options.sourceMaps);
+	t.false(options.ast);
+	t.true('inputSourceMap' in options);
+	t.false(options.babelrc);
+	t.same(options.presets, ['stage-2', 'es2015']);
+	t.same(options.plugins, [customPlugin, powerAssert, transformRuntime]);
+	t.end();
+});