gulpfile.js

var gulp = require('gulp');
var uglify = require('gulp-uglify');
var ts = require('gulp-typescript');
var webserver = require('gulp-webserver');
var gulp = require('gulp');
var sass = require('gulp-sass');
var shell = require('gulp-shell');
var jasmine = require('gulp-jasmine-phantom');
var KarmaServer = require('karma').Server;

gulp.task('sass', function () {
    gulp.src('app/sass/**/*.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(gulp.dest('./css'));
});
gulp.task('sassw', function(){
	gulp.watch('app/sass/**/*.scss', gulp.series("sass"));
});

 
gulp.task('compress', function() {
 return gulp.src('build/**/*.js')
   .pipe(uglify())
   .pipe(gulp.dest('build'));
});

var tsProject = ts.createProject('tsconfig.json');

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

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

gulp.task('lite', shell.task([
    'lite-server'
]));
gulp.task('tscw', function () {
    gulp.watch('app/**/*.ts', gulp.series('tsc'));
});

gulp.task('server', function(){
    gulp.src('./', '!/**/*.ts')
        .pipe(webserver({
        livereload: true,
        directoryListing: true,
        open: 'index.html'
        }));
});

gulp.task('develop', 
    gulp.series('tsc', 
        gulp.parallel('server','tscw', 'sassw')
    )
);

gulp.task('build',
    gulp.series('tsc','compress')
);

gulp.task('test', function (done) {
  new KarmaServer({
    configFile: __dirname + '/karma.conf.js',
    singleRun: true
  }, done).start();
});

gulp.task('testw', function (done) {
  new KarmaServer({
    configFile: __dirname + '/karma.conf.js',
    autoWatch: true
  }, done).start();
});