Error from uglify in compress task Error in plugin 'gulp-uglify'

Follow this example with uglifyes or use Babel or (if you use it) TypeScript to output to ES5.

Make sure to read the documentation more closely.

Example:

var uglifyes = require('uglify-es'); // for ES support
var composer = require('gulp-uglify/composer'); // for using a different uglify runtime/config

var uglify = composer(uglifyes, console); // setup the new uglify constant

function javascriptTask ( done ) {

    gulp.src("[[file location]]")
        // [pipe processing]
        .pipe(uglify())
    done(); // this tells Gulp 4 that the task is done
    
}

let main = gulp.[series | parallel](javascriptTask); // edit out series or parallel depending on needs

export default = main // allows you launch all tasks in the gulp.[series | parallel] from the terminal with gulp

You can also use gulp-terser

For transpiling

For a babel solution: click here

If you use TypeScript you should have target : 'es5' in your .tsconfig, tsify (for browserify) or gulp-typescript object.