TypeScript compilation extremely slow > 12s

问题:

Just putting this out there to see if someone else is having this issue...

I have building an angular 2 app with typescript using webpack as my build tool, it all works well, however I have noticed typescript compilation is super super slow, I am at 12 seconds right now...., and its pretty clear that is all due to the typescript compilation process....

I have used ts-loader or awesome-typescript-loader with a similar result, if I comment out this loader, my build time drops to around 1 sec....

After some research it seems like its 'normal' to have 'slow' times when compiling typescript, but is 12secs the normal??

Old posts hinted it might be due to a node version conflict, I am currently running v4.4.2...

Any how below is my webpack code in case anyone spots something wrong there.. the commented code in the Uglify section is due to some 'bug' on the angular 2 side...

const path = require('path');
const merge = require('webpack-merge');
const webpack = require('webpack');

const NpmInstallPlugin = require('npm-install-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const TARGET = process.env.npm_lifecycle_event;

const PATHS = {
  app: path.join(__dirname, 'app'),
  dist: path.join(__dirname, 'dist')
};

const common = {
  entry: {
    vendor: ['./app/vendor.ts'],
    main: ['./app/boot.component.ts']
  },
  output: {
    filename: '[name].[hash].bundle.js',
    path: PATHS.dist
  },
  resolve: {
    extensions: ['', '.js', '.ts']
  },
  plugins: [
    new HtmlWebpackPlugin({
      title: 'Qarrot Performance',
      template: 'index.template.ejs',
      commonStyles: [
        '/public/styles/vendor/normalize.css',
        '/public/styles/main.css'
      ],
      commonScripts: [],
      baseHref: '/',
      unsupportedBrowser: true,
      mobile: true,
      appMountId: 'app'
    }),
  ],
  module: {
    loaders: [
      {
        test: /\.ts$/,
        exclude: /node_modules/,
        loaders: ['ts-loader']
      },
      {
        test: /\.scss$/,
        loader: 'raw-loader!sass-loader'
      },
      {
        test: /\.html$/,
        loader: "html"
      }
    ]
  }
}

// Dev Settings
if(TARGET === 'start' || !TARGET) {
  module.exports = merge(common, {
    devtool: 'eval-source-map',
    devServer: {
      contentBase: PATHS.build,
      historyApiFallback: true,
      hot: true,
      inline: true,
      progress: true,
      stats: 'errors-only',
    },
    plugins: [
      new webpack.HotModuleReplacementPlugin(),
      new NpmInstallPlugin({
        save: true
      })
    ]
  });
}

// Prod Settings
if(TARGET === 'build') {
  module.exports = merge(common, {
    devtool: 'cheap-module-source-map',
    plugins: [
      // new webpack.optimize.UglifyJsPlugin({
      //   beautify: false,
      //   mangle: false,
      //   compress : { screw_ie8 : true },
      //   comments: false
      // }),
      new webpack.optimize.DedupePlugin(),
      new webpack.DefinePlugin({
        'process.env.NODE_ENV': '"production"'
      }),
      new CopyWebpackPlugin([
            { from: 'public', to: 'public' }
      ]),
      new webpack.optimize.CommonsChunkPlugin({
        names: ['vendor', 'manifest']
      }),
    ]
  });
}

I am also on a Mac, running Angular 2 beta.15 and webpack version 1.12, below is my tsconfig.json

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": false,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false
  },
  "compileOnSave": false,
  "exclude": [
    "node_modules",
    "typings/main",
    "typings/main.d.ts"
  ]
}

回答1:

I would stick to the awesome-typescript-loader. It has some performance options you can enable: a caching option and a transpile only option:

"awesomeTypescriptLoaderOptions": {
  "useCache": true,
  "transpileOnly": true
}

Both of these had a significant improvement on compile times.

回答2:

Please share you tsconfig.json. Most likely you have noEmitOnError set to true which means that the compiler is forced to typecheck the whole codebase before any emitting.

Please set that to false.