ast-plugins.js #1

/* jshint node: true */
'use strict';

const fs = require('fs');
const path = require('path');

const HTMLBarsInlinePrecompilePlugin = require('babel-plugin-htmlbars-inline-precompile');

const pluginCache = {};

module.exports = {
  setup(pluginInfo, options) {
    // borrowed from ember-cli-htmlbars http://git.io/vJDrW
    let projectConfig = options.projectConfig || {};
    let templateCompilerPath = options.templateCompilerPath;
    let useCache = options.useCache;

    let EmberENV = projectConfig.EmberENV || {};

    // ensure we get a fresh templateCompilerModuleInstance per ember-addon
    // instance NOTE: this is a quick hack, and will only work as long as
    // templateCompilerPath is a single file bundle
    //
    // (╯°□°）╯︵ ɹǝqɯǝ
    //
    // we will also fix this in ember for future releases
    delete require.cache[templateCompilerPath];

    // do a full clone of the EmberENV (it is guaranteed to be structured
    // cloneable) to prevent ember-template-compiler.js from mutating
    // the shared global config
    let clonedEmberENV = JSON.parse(JSON.stringify(EmberENV));
    global.EmberENV = clonedEmberENV;

    let Compiler = require(templateCompilerPath);
    let cacheKey = this.makeCacheKey(templateCompilerPath, pluginInfo);

    let precompileInlineHTMLBarsPlugin;

    // babel memoizes every plugin it sees,
    // and creating a new plugin for every transpilation will eventually overflow the heap
    // so use a local cache to avoid that
    if (useCache && pluginCache[cacheKey] !== undefined) {
      precompileInlineHTMLBarsPlugin = pluginCache[cacheKey];
    } else {
      pluginInfo.plugins.forEach((plugin) => Compiler.registerPlugin('ast', plugin));

      let precompile = Compiler.precompile;
      precompile.baseDir = () => path.resolve(__dirname, '..');
      precompile.cacheKey = () => cacheKey;

      precompileInlineHTMLBarsPlugin = [HTMLBarsInlinePrecompilePlugin, { precompile  }];
      pluginCache[cacheKey] = precompileInlineHTMLBarsPlugin;
    }

    delete require.cache[templateCompilerPath];
    delete global.Ember;
    delete global.EmberENV;

    return precompileInlineHTMLBarsPlugin;
  },

  makeCacheKey(templateCompilerPath, pluginInfo, extra) {
    require(templateCompilerPath);
    let templateCompilerFullPath = require.resolve(templateCompilerPath);
    let templateCompilerCacheKey = fs.readFileSync(templateCompilerFullPath, { encoding: 'utf-8' });
    let cacheItems = [templateCompilerCacheKey, extra].concat(pluginInfo.cacheKeys.sort());
    // extra may be undefined
    return cacheItems.filter(Boolean).join('|');
  }
};