Gulp: The following tasks did not complete: default, js Did you forget to signal async completion

Just started learning gulp and followed this tutorial series:

It works perfectly on gulp 3 but after updating npm to the current version it broke down and i tried converting my gulpfile.js from version 3 to 4, and after running the gulp command i have this error: The following tasks did not complete: default, Did you forget to signal async completion? How do i solve this?

Here’s my gulpfile:

const gulp = require('gulp');
const rename = require('gulp-rename');
const sass = require('gulp-sass');
const uglify = require('gulp-uglify');
const autoprefixer = require('gulp-autoprefixer');
const sourcemaps = require('gulp-sourcemaps');
const browserify = require('browserify');
const babelify = require('babelify');
const source = require('vinyl-source-stream');
const buffer = require('vinyl-buffer');

let styleSource = 'src/scss/style.scss';
let styleDestination = './build/css/';
let styleWatch = 'src/scss/**/*.scss';

let jsSource = 'main.js';
let jsFolder = 'src/js/';
let jsDestination = './build/js/';
let jsWatch = 'src/js/**/*.js';
let jsFILES = [jsSource];    
let htmlWatch = '**/*.html';

/* Converting Sass to CSS */
    return gulp.src(styleSource)
            errorLogToConsole: true,
            outputStyle: 'compressed'
        .on('error', console.error.bind(console))
            browsers: ['last 2 versions'],
            cascade: false

/* Converting ES6 to Vanilla JS */
        return browserify({
            entries: [`${jsFolder}${entry}`]
        .transform(babelify, {presets:['env']})
        .pipe( rename({extname:'.min.js'}) )
        .pipe(sourcemaps.init({loadMaps: true})) 


// default task to run all tasks
const compile = gulp.parallel(['styles','js']);
compile.description = 'Compile all styles and js files';

gulp.task('default', compile);

// watch default
const watch = gulp.series('default', function(){ // ,'browser-sync'
// keep running, watching and triggering gulp, gulp.parallel('styles')); //, reload, gulp.parallel('js')); //, reload;
watch.description = 'watch all changes in every files and folders';
gulp.task('watch', watch);