comments for npm package.json with a grunt.js task

Gruntfile.js

/*jslint node: true */
'use strict';

module.exports = function (grunt) {

    /*
        1. make package.json.js and export the json that will be saved as package.json
        2. run grunt package.json, the new file will be written and you get a patch as well
    */
    grunt.registerTask('package.json', function () {

        var fs = require('fs');
        var pnew = require('./package.json.js');
        var pcurrent = JSON.parse(fs.readFileSync('./package.json'));

        var x = require('xdiff')

        var diff = x.diff(pcurrent, pnew);

        if (diff) {
            console.log('Writing new package.json with changes:');
            console.log(diff);
            fs.writeFileSync('./package.json', JSON.stringify(pnew, null, '  '));
        } else {
            console.log('No changes.');
        }
    });
};

package.json

{
  "name": "your-project",
  "version": "0.0.0",
  "private": true,
  "dependencies": {},
  "devDependencies": {
    "xdiff": "^0.2.11",
    "grunt": "^0.4.5"
  }
}

package.json.js

'use strict';

/*
    You can use any kind of valid javascript comments in this file.
    - marko
    
    ps: you could also use this script to dynamicaly create a package.js
*/

module.exports = {
  "name": "your-project",
  "version": "0.0.0",
  "private": true,
  "dependencies": {
	  // place your project dependencies here
  },
  "devDependencies": {
	  
    // comments are execial to quickly assert the state of a dependency
    "xdiff": "^0.2.11",
	
	// we still need grunt 
	"grunt": "^0.4.5"
  }
};

how do you ensure the very first run? Means how do you pull grunt itself since the package.json is missing?

sorry, missed your comment.
simple, you destribute the script with the package.json prebuild, its just a build script anyway

Interesting idea. But what do you do when you install a new package with eg. --save-dev and your package.json is updated directly?