Grunt - 在运行任务之前动态设置配置

Question

So here is my hypothetical config object for a hypothetical fooTask that does something (not relevant to question) to a bunch of JS files

grunt.initConfig({
  fooTask: {
    app1: 'app1/*.js',
    app2: 'app2/*.js',
    app3: 'app3/*.js'
  }
});

As you can see, with this approach, I have to run fooTask 3 times with each app specified as a target:

grunt fooTask:app1
grunt fooTask:app2
grunt fooTask:app3

Needless to say this does not scale as either the number of apps increase or the number of such foo tasks increase as one has to C&P the same code over and over for each app.

So ideally what I would like to define is just one target with the name of the app passed in as a config variable

grunt.initConfig({
  fooTask: {
    dist: '<%=appName%>/*.js'
  }
});

I would then like to call fooTask 3 times, one for each app, with the right app set as appName

var apps = ['app1', 'app2', 'app3'];
apps.forEach(function(app) {
  var currAppName = app;

  // Run fooTask but how do I specify the new currAppName config?
  grunt.task.run('fooTask');
});

As from code above, I know I can run my fooTask using grunt.task.run but how do I set the appName config for my task?

Note that this question is similar to this other one that also does not have the right answer yet - Pass Grunt config options from task.run

Thanks a lot.

Answer 1

EDIT 2:

So nevermind the garbage below the first edit, leaving as example of what doesn't work. In my case it was really important to be able to set the value within a task at run-time so I settled on the file system. Perhaps it suits your needs.

grunt.initConfig({
  someTask: {
    someKey: fs.readFileSync('file.txt', { encoding: 'utf8' })
  }
});

of course you can do the readFile outside of the task if you need a bunch of different app names.

---

EDIT: Hmmm. I swear I had this working when I wrote this...but now it is not. Grunt just sees the extra arguments as additional unfound tasks.

---

I was trying to figure this out myself, finally a "duh" just moment happened - why not parse process.argv before grunt.initConfig ?

module.exports = function(grunt) {

  var sourcefile = process.argv[2] || 'default.js'; // <- this

  grunt.initConfig({
    uglify: {
      main: {
        src: sourcefile, // <- voila :)
        dest: sourcefile.substring(0, sourcefile.length-3) + '.min.js'
      }
    }
  });

  grunt.loadNpmTasks('uglify');

  grunt.registerTask('default', ['uglify']);
};

and use from command line:

grunt mykillerscript.js

I didn't even try to use grunt.option for the same reason that all the examples only showed directing which task is run, but I wouldn't be surprised if there is a more "grunt" way to do this.