How to uglify output with Browserify in Gulp?

I tried to uglify output of Browserify in Gulp, but it doesn't work. gulpfile.js var browserify = require('browserify'); var gulp = require('gulp'); var uglify = require('gulp-uglify'); var source = require('vinyl-source-stream'); gulp.task('browserify', function() { return browserify('./source/scripts/app.js') .bundle() .pipe(source('bundle.js')) .pipe(uglify()) // ??? .pipe(gulp.dest('./build/sc