Source order is not respected when using Grunt templates

[argyleink]

This is maintained:

module.exports = (grunt) ->
  prod:
    options:
      banner:     "<%= banner %>"
      screwIE8:   true
      compress:   drop_console: true
    files: 
      "<%= dirs.build %>/js/app.js": [
        "js/bower/material-design-lite/material.js"
        "js/app.js"
      ]

This works if app.js is not modified:

module.exports = (grunt) ->
  prod:
    options:
      banner:     "<%= banner %>"
      screwIE8:   true
      compress:   drop_console: true
    files: 
      "<%= dirs.build %>/js/app.js":"<%= app.js %>"

This DOES NOT work, src order is lost:

module.exports = (grunt) ->
  prod:
    options:
      banner:     "<%= banner %>"
      screwIE8:   true
      compress:   drop_console: true
    files: 
      "<%= dirs.build %>/js/app.js":"<%= app.js.map((file)=>`app/${file}`) %>"

If i use uglifyjs2 straight from shell using the below, it works. Therefore, I believe it's grunt-contrib-uglify's fault for the reordering of src code during concat. Please advise.

./node_modules/uglify-js/bin/uglifyjs <%= app.js.map((file)=>app/${file}).toString().replace(',', ' ') %> -o build/dev/js/app.min.js

[XhmikosR]

#271