retire feature flag directive

gistfile1.js

  // given the markup: <a href="#hashtag" feature-flag="phaseTwo" class="whatevs-yo">don't click</a>
  // and the task to "retire" feature flag settings from the markup (ie B-03572)
  // grunt feature --retire=phaseTwo
  module.exports = function(grunt) {
      grunt.initConfig({
          dom_munger: {
              feature_flags: {
                  src: ['path/to/views'],
                  options: {
                      callback: function($, file) {
                          var flag = 'feature-flag';
                          $('[' + flag + ']').filter(function() {
                              if ($(this).attr(flag) === grunt.option('retire')) {
                                  $(this).removeAttr(flag);
                              }
                          });
                      }
                  }
              }
          }
      });
      grunt.loadNpmTasks('grunt-dom-munger');
      grunt.registerTask('feature', ['dom_munger:feature_flags']);
  };

  // expected output: <a href="#hashtag" class="whatevs-yo">don't click</a>