How do I rewrite this gulpfile.js in gulp version 4.0?

Question

JavaScript

I got an error when I wrote the following in gulpfile.js:

var gulp							 = require('gulp'),
        sass							 = require('gulp-sass'),
        browserSync = require('browser-sync'),
        concat      = require('gulp-concat'),
        uglify      = require('gulp-uglifyjs');	
        
gulp.task('sass', function() {
  return gulp.src('app/sass/**/*.sass')
                .pipe	(sass())
                .pipe(gulp.dest('app/css'))
                .pipe(browserSync.reload({stream: true}))
});

gulp.task('scripts', function() {
          return gulp.src([
                  'app/libs/jquery/dist/jquery.min.js',
                  'app/libs/magnific-popup/dist/jquery.magnific-popup.min.js',
          ])
          .pipe(concat('libs.min.js'))
          .pipe(uglify())
          .pipe(gulp.dest('app/js'));
});

gulp.task('browser-sync', function() {
  browserSync({
    server: {
            baseDir: 'app'
    },
    notify: false		
  });
});

gulp.task('watch', function() {
    gulp.watch('app/sass/**/*.sass', gulp.parallel('sass')); // Наблюдение за sass файлами
    gulp.watch('app/*.html', gulp.parallel('code')); // Наблюдение за HTML файлами в корне проекта
    gulp.watch(['app/js/common.js', 'app/libs/**/*.js'], gulp.parallel('scripts')); // Наблюдение за главным JS файлом и за библиотеками
});
gulp.task('default', gulp.parallel('sass', 'scripts', 'browser-sync', 'watch'));

Mistake:

Answer 1

your error is not related to galp versions at all, you just don't have a task with the name "code"
and so, use exports insteadgulp.task

function sassToCss() {
 // ...
}
exports.sass = sassToCss;