Angular2 compilation

gulpfile.js

'use strict';
 
var gulp = require('gulp');
var sass = require('gulp-sass');
var ts = require('gulp-typescript');
var tsProject = ts.createProject('tsconfig.json', {typescript: require('typescript')});

var paths = {
	sass: ['./resources/sass/**/*.scss'],
	ts: ['./resources/app/**/*.ts'],
	css: './css',
}
 
gulp.task('sass', function () {
  return gulp.src(paths.sass)
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest(paths.css));
});

gulp.task('ts', function() {
    var tsResult = tsProject.src()
        .pipe(ts(tsProject));

    return tsResult.js.pipe(gulp.dest('./app'));
});

gulp.task('default', ['sass', 'ts']);

gulp.task('watch', function () {
  gulp.watch(paths.sass, ['sass']);
  gulp.watch(paths.ts, ['ts']);
});

tsconfig.json

{
  "compilerOptions": {
    "target": "es5",
    "module": "system",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false,
    "rootDir": "resources/app/",
    "outDir": "app/"
  },
  "exclude": [
    "node_modules"
  ]
}