gulpfile.js

var gulp = require('gulp');
var uglify = require('gulp-uglify');
var rename = require('gulp-rename');

// concat-js definition ...

gulp.task('uglify', ['concat-js'], function() {
	return gulp.src('./dist/wysiwyg.js')
		.pipe(uglify())
		.pipe(rename(function (path) {
			path.basename += ".min";
			return path;
		}))
		.pipe(gulp.dest('./dist'));
});