Engine_Rebuild/gulpfile.js

const {src, dest, series} = require('gulp');
const del = require('del');
const ts = require('gulp-typescript');
let tsSource = ts.createProject('tsconfig.json')

let pageFiles = ['src/assets/pages/**', 'src/assets/pages/scripts/*', 'src/assets/pages/styles/*']

function clean(cb){
    del(['build/*']);
    cb();
}

function conf(){
    return src('src/assets/**/*', {base: 'src/assets'})
        .pipe(dest('build/assets/'));
}


function root(){
    return src('src/*.js')
        .pipe(dest('build/'));
}
function pkg(){
    return src('package*')
        .pipe(dest('build/'));
}

function typescript(){
    return tsSource.src()
        .pipe(tsSource()).js
        .pipe(dest('build/util/'));
}

exports.clean = clean;

exports.default = series(conf, root, pkg, typescript);