metro/packages/metro-bundler/transformer.js

170 lines
4.8 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* Note: This is a fork of the fb-specific transform.js
*
* @flow
*/
'use strict';
const babel = require('babel-core');
const crypto = require('crypto');
const externalHelpersPlugin = require('babel-plugin-external-helpers');
const fs = require('fs');
const generate = require('babel-generator').default;
const inlineRequiresPlugin = require('babel-preset-fbjs/plugins/inline-requires');
const json5 = require('json5');
const makeHMRConfig = require('babel-preset-react-native/configs/hmr');
const path = require('path');
const resolvePlugins = require('babel-preset-react-native/lib/resolvePlugins');
const {compactMapping} = require('./src/Bundler/source-map');
import type {Plugins as BabelPlugins} from 'babel-core';
import type {Transformer, TransformOptions} from './src/JSTransformer/worker/worker';
const cacheKeyParts = [
fs.readFileSync(__filename),
require('babel-plugin-external-helpers/package.json').version,
require('babel-preset-fbjs/package.json').version,
require('babel-preset-react-native/package.json').version,
];
/**
* Return a memoized function that checks for the existence of a
* project level .babelrc file, and if it doesn't exist, reads the
* default RN babelrc file and uses that.
*/
const getBabelRC = (function() {
let babelRC: ?{extends?: string, plugins: BabelPlugins} = null;
return function _getBabelRC(projectRoot) {
if (babelRC !== null) {
return babelRC;
}
babelRC = {plugins: []};
// Let's look for the .babelrc in the project root.
// In the future let's look into adding a command line option to specify
// this location.
let projectBabelRCPath;
if (projectRoot) {
projectBabelRCPath = path.resolve(projectRoot, '.babelrc');
}
// If a .babelrc file doesn't exist in the project,
// use the Babel config provided with react-native.
if (!projectBabelRCPath || !fs.existsSync(projectBabelRCPath)) {
babelRC = json5.parse(
fs.readFileSync(
path.resolve(__dirname, 'rn-babelrc.json'))
);
// Require the babel-preset's listed in the default babel config
// $FlowFixMe: dynamic require can't be avoided
babelRC.presets = babelRC.presets.map(preset => require('babel-preset-' + preset));
babelRC.plugins = resolvePlugins(babelRC.plugins);
} else {
// if we find a .babelrc file we tell babel to use it
babelRC.extends = projectBabelRCPath;
}
return babelRC;
};
})();
/**
* Given a filename and options, build a Babel
* config object with the appropriate plugins.
*/
function buildBabelConfig(filename, options) {
const babelRC = getBabelRC(options.projectRoot);
const extraConfig = {
code: false,
filename,
};
let config = Object.assign({}, babelRC, extraConfig);
// Add extra plugins
const extraPlugins = [externalHelpersPlugin];
var inlineRequires = options.inlineRequires;
var blacklist = typeof inlineRequires === 'object' ? inlineRequires.blacklist : null;
if (inlineRequires && !(blacklist && filename in blacklist)) {
extraPlugins.push(inlineRequiresPlugin);
}
config.plugins = extraPlugins.concat(config.plugins);
if (options.hot) {
const hmrConfig = makeHMRConfig(options, filename);
config = Object.assign({}, config, hmrConfig);
}
return Object.assign({}, babelRC, config);
}
type Params = {
filename: string,
options: TransformOptions,
plugins?: BabelPlugins,
src: string,
};
function transform({filename, options, src}: Params) {
options = options || {};
const OLD_BABEL_ENV = process.env.BABEL_ENV;
process.env.BABEL_ENV = options.dev ? 'development' : 'production';
try {
const babelConfig = buildBabelConfig(filename, options);
const {ast, ignored} = babel.transform(src, babelConfig);
if (ignored) {
return {
ast: null,
code: src,
filename,
map: null,
};
} else {
const result = generate(ast, {
comments: false,
compact: false,
filename,
sourceFileName: filename,
sourceMaps: true,
}, src);
return {
ast,
code: result.code,
filename,
map: options.generateSourceMaps ? result.map : result.rawMappings.map(compactMapping),
};
}
} finally {
process.env.BABEL_ENV = OLD_BABEL_ENV;
}
}
function getCacheKey() {
var key = crypto.createHash('md5');
cacheKeyParts.forEach(part => key.update(part));
return key.digest('hex');
}
module.exports = ({
transform,
getCacheKey,
}: Transformer<>);