Gulp function not working after updating to version 4 - gulp

Question

I have updated Gulp 3.9 to 4 and my gulp task is now returning an Assertion Error: Task function must be specified.
Can anyone show how I could refactor the code below to work with Gulp 4?
Thanks in advance!
gulp.task('default', ['sass', 'browser-sync'], function () {
gulp.watch("./scss/**/*.scss", ['sass']);
gulp.watch("./js/main.js", ['javascript']);
});

Answer 1

gulp.task('default', gulp.series('sass', 'browser-sync', function () {
gulp.watch("./scss/**/*.scss", 'sass');
gulp.watch("./js/main.js", 'javascript');
}));
should do it. The function signature has changed (from 3 to 2 parameters) and you need to use gulp.series.
See Convert gulp watch in gulp#3.9.1 to gulp#4

Answer 2

// compile scss into css
function style() {
// 1. where is my scss file
return gulp.src('./app/scss/**/*.scss')
// 2. pass that file through sass compiler
.pipe(sass().on('error', sass.logError))
// 3. where do I save the compiled CSS?
.pipe(gulp.dest('./app/css'))
// 4. stream changes to all browser
.pipe(browserSync.stream());
}
function watch() {
browserSync.init({
server: {
baseDir: './app/'
}
});
gulp.watch('./app/scss/**/*.scss', style);
gulp.watch('./app/**/*.html').on('change', browserSync.reload);
gulp.watch('./app/js/**/*.js').on('change', browserSync.reload);
}
exports.style = style;
exports.watch = watch;
Faced same issue and I found this code in this youtube video
Hope this helps.