Add custom new lines with Gulp uglify and Concat

Question

I am using Gulp and gulp uglify and concat to create production JS. How can I add new lines before license comments?

Example output

/*! Version 1 */
function Test1(){}/*! Version 2 */
function Test(){}

Desired output

/*! Version 1 */
function Test1(){}
/*! Version 2 */
function Test(){}

My code that wraps the gulp sequence

function gulpDeploy(src, fileName, dest){
    gulp.src(src)
        .pipe(concat(fileName, {
            newLine:'\n;'
        }))
        .pipe(uglify({
            preserveComments : 'license'
        }))
        .pipe(gulp.dest(dest));
}

It looks like the newLine option should do it, but it doesn't do anything..

Answer 1

I'd be very interested in seeing alternative answers that use just uglify and concat to do this, but a naive fix using gulp-replace would be this:

var gulp = require('gulp');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var replace = require('gulp-replace');

gulp.task('default', [], function() {
  gulp.src('file*.js')
    .pipe(concat('output.js', { newLine: '\n;' }))
    .pipe(uglify({ preserveComments: 'license' }))
    .pipe(replace(/(\/\*\! Version [^*]* \*\/)/g, '\n$1')) // Version-comments to new line
    .pipe(replace(/^\s*\r?\n/gm, '')) // Remove empty lines that may get left
    .pipe(gulp.dest('./build'));
});

I would've preferred to have the first regex find only Version-comments that don't already start on the start of a new line (so the second replace call wouldn't be needed), but it seemed quite hard to get that regex to work (for one because negative lookbehind doesn't seem to work, or I'd think you could use (?<!^)\/\*\! Version [^*]* \*\/ to do it...)