Example Grunt-Init Conditional Copy

rename.json

{
  "app/js/main-empty.js": "{% if (empty) { %}app/js/main.js{% } %}",
  "app/js/main-skeleton.js": "{% if (!empty) { %}app/js/main.js{% } %}"
}

template.js

'use strict';

// Template Infos
exports.description = 'Conditional copy example';
exports.notes = 'This template is an example of conditional copying.';
exports.warnOn = 'Gruntfile.js';
exports.warnOn = 'package.json';

// Template Init
exports.template = function (grunt, init, done) {
  
  // Prompts
  init.process({}, [
    init.prompt('name', 'ProjectName'),
    init.prompt('description', 'Project description...'),
    init.prompt('version', '0.0.1'),
    init.prompt('homepage'),
    {
      name: 'empty',
      message: 'Empty main or setup?',
      default: 'Y/n',
      warning: ''
    }
    ], function (err, props) {
    var files;

    // YepNope Dependencies
    props.empty = /y/i.test(props.empty);

    // Output Template
    files = init.filesToCopy(props);
    init.copyAndProcess(files, props);
    init.writePackageJSON('package.json', props);

  })

};

Example for question here on copying files with grunt-init