how to minify js files in order via grunt-contrib-

Question

I have a directory like below:

/folder/b.js
/folder/jQuery.js
/folder/a.js
/folder/sub/c.js

I want to minify all these js files in one js file in order:

jQuery.js -> a.js -> b.js -> c.js

Q:
1.How can I do it via grunt-contrib-uglify?(In fact, there are lots of files, it is impractical to specify all source filepaths individually)

2.btw, How can I get unminified files when debug and get minified single file when release and no need to change script tag in html(and how to write the script tag)?

Answer 1

You're probably not going to like this, but the best way is to define your js source files as AMD modules and use Requirejs to manage the order in which they load. The grunt-contrib-requirejs task will recurse your dependency tree and concatenate the js files in the necessary order into one big js file. You will then use uglify (actually r.js has uglify built-in) to minify the big file.

https://github.com/danheberden/yeoman-generator-requirejs has a good example gruntfile and template js files to work from.

EDIT

I've recently started using CommonJS modules instead of AMD since it's much closer to the ES6 module spec. You can achieve the same results (1 big complied+concatenated js file) by running commonjs modules through Browserify. There are plugins for both grunt and gulp to manage the task for you.

EDIT

I'd like to add that if your site is written using ES6 that Rollup is the best new concatenating package. In addition to bundling your files, it will also perform tree shaking, removing parts of libraries you use if included via an import statement. This reduces your codebase to just what you need without the bloat of code you'll never use.

Answer 2

Looks like the second part of your question is still unanswered. But let me try one by one.

Firstly you can join and uglify a large number of js files into one as explained by the concat answer earlier. It should also be possible to use https://github.com/gruntjs/grunt-contrib-uglify because it does seem to have wildcards. You may have to experiment with 'expand = true' option and wildcards. That takes care of your first question.

For the second part, say you joined and uglified into big-ugly.js

Now in your html you can add following directives:

<!-- build:js:dist big-ugly.js -->
<script src="js1.js"></script>
<script src="js2.js"></script>
<!-- etc etc --> 
<script src="js100.js"></script>
<!-- /build -->

And then pass it through the grunt html preprocessor at https://www.npmjs.com/package/grunt-processhtml as part of your grunt jobs.

This preprocessor will replace the entire block with

<script src="big-ugly.js"></script>

Which means that the html file with be semantically equivalent - before and after the grunt jobs; i.e. if the page works correctly in the native form (for debugging) - then the transformed page must work correctly after the grunt - without requiring you to manually change any tags.

Answer 3

I don't think you can do this with the uglify task alone, but you have a multitude of choices which might lead to your desired outcome.

A possible workflow would be first concatenating (grunt-contrib-concat) the files in order into one single file, and put this concatenated file through uglify. You can either define the order for concat in your Gruntfile, or you use on of those plugins:

First one would be https://github.com/yeoman/grunt-usemin, where you can specify the order in your HTML file, put some comments around your script block. The Google guys made it and it's pretty sweet to use.

Second one would be https://github.com/trek/grunt-neuter, where you can define some dependencies with require, but without the bulk of require.js. It requires changes in your JS code, so might not like it. I'd go with option one.

Answer 4

Good questions!

1) Uglify will reorder the functions in the destination file so that function definitions are on top and function execution on bottom but it seems that it will preserve the order of the function executions.

This means that the function jQuery runs to define its global functions will be put first if you make sure jQuery is mentioned first in Uglify's config in the Gruntfile.

I use this config:

uglify: {
    options: {
        sourceMap: true
    },
    build: {
        files: {
            'public/all.min.js': ['public/js/vendor/jquery-1.10.2.min.js', 'public/js/*.js'],
        }
    }
}

2) I don't think there is one definite way to accomplish this. It depends on what web framework, templating framework and what kind of requirements you have. I use express + jade and in my main jade layout I have:

if process.env.NODE_ENV === 'production'
  script(src='/all.min.js')
else
  script(src='/js/vendor/jquery-1.10.2.min.js')
  script(src='/js/someScript.js')
  script(src='/js/otherScript.js')

In my package.json I have:

"scripts": {
  "postinstall": "grunt"
},

This means that when I run npm install on deploy (on Heroku) grunt is run to minify/concat files and when the app is started with NODE_ENV=production the minified client side javascript is used. Locally I get served the original client side javascripts for easy debugging.

The two downsides are:

• I have to keep the two lists of script files in sync (in the Gruntfile and in the layout.js) I solve this by using *.js in the Gruntfile but this may not suite everyone. You could put the list of javascripts in the Gruntfile and create a jade-template from this but it seems overkill for most projects.
• If you don't trust your Grunt config you basically have to test running the application using NODE_ENV=production locally to verify that the minification worked the way you intended.

Answer 5

This was @1469's answer but he didn't make it clear why this works. Use concat to put all js files into one, this module does this in the order of file names, so I put a prefix to the file names based on orders. I believe it even has other options for ordering.

concat: {

        js: {
            options: {
                block: true,
                line: true,
                stripBanners: true
            },
            files: {
                'library/dist/js/scripts.js' : 'library/js/*.js',
            }
        }
    },

Then use uglify to create the minified ugly version:

uglify: {
      dist: {
        files: {
          'library/dist/js/scripts.min.js': [
            'library/js/scripts.js'
          ]

        },
        options: {

        }
      }
    },

Answer 6

If your problem was that you had vendors which needed to be loaded in order (let's say jquery before any jquery plugins). I solved it by putting jquery in its own folder called '!jquery', effectively putting it on top of the stack. Then I just used concat as you normally would:

concat: {
  options: {
    separator: ';',
  },
  build: {
    files: [
      {
        src: ['js/vendor/**/*.js', 'js/main.min.js'],
        dest: 'js/global.min.js'
      }
    ]
  }
},