Grunt task for TypeScript compilation

grunt-typescript.js

module.exports = function(grunt) {
  'use strict';

  // TODO: ditch this when grunt v0.4 is released
  grunt.util = grunt.util || grunt.utils;

  var async = grunt.util.async;

  grunt.registerMultiTask('typescript', 'Compile TypeScript to JavaScript', function() {
    var helpers = require('grunt-contrib-lib').init(grunt),
        path = require('path'),
        options = helpers.options(this),
        cb = this.async(),
        args = helpers.optsToArgs(options);

    grunt.verbose.writeflags(options, 'Options');

    // TODO: ditch this when grunt v0.4 is released
    this.files = this.files || helpers.normalizeMultiTaskFiles(this.data, this.target);
    async.forEachSeries(this.files, function(el, cb2) {
      el.dest = path.normalize(el.dest);

      var srcFiles = grunt.file.expandFiles(el.src),
          useOutParam = !helpers.isIndividualDest(el.dest);

      if (useOutParam) {
        args = args.concat(['--out', el.dest]);

        // Make sure grunt creates the destination folders
        grunt.file.write(el.dest, '');
      }

      args = args.concat(srcFiles);

      var tsc = grunt.util.spawn({
        cmd: 'tsc',
        args: args
      }, function(error, result, code){

        cb2(code > 0);

      }).on('exit', function (code){
        if (code !== 0) {
          grunt.warn('Error code ' + code + ' returned from tsc.');
        } else if (useOutParam && !!options.sourcemap) {
            // fix pathing in source maps. tsc computes relative paths correctly only
            // if the source .ts exists within the same relative dir as the outfile
            var sourcemapPath = el.dest + '.map',
                sourcemapContents = grunt.file.read(sourcemapPath),
                absolutePart = process.cwd()+'/app',
                fixedContents =
                  sourcemapContents.replace(new RegExp(absolutePart, 'g'), '');

            grunt.file.write(sourcemapPath, fixedContents);
        }
      });

      tsc.stdout.pipe(process.stdout);
      tsc.stderr.pipe(process.stderr);

    }, function(error) {
      cb(!error);
    });
  });
};