[AngularJS] basic countdown. angular version of (https://gist.github.com/srph/fcd27d3e87a483b26ee9)

CountdownControl.js

'use strict';

angular
	.module('app')
	.directive('CountdownControl', CountdownControl);

  function CountdownControl() {
    var template = [
      '<span ng-click="controlCtrl.toggleTick()">',
        '{{ controlCtrl.state }}',
      '</span>'
    ].join('');

    return {
      scope: {
        flag: '=',
        resume: '&',
        pause: '&'
      }
      require: '^CountdownTimer'
      template: template,
      controller: controller,
      controllerAs: 'controlCtrl'
    }
    function controller($scope) {
      var vm = this;

      vm.state = vm.flag ? 'Pause' : 'Resume';
      vm.toggleTick = toggleTick;

      function toggleTick() {
        if ( angular.isUndefined(vm.flag) ) {
          vm.pause();
        } else {
          vm.resume();
        }
      }
    }
  }

CountdownTimer.js

'use strict';

angular
  .module('app')
  .directive('CountdownTimer', CountdownTimer);

  function CountdownTimer() {
    /** Directive template */
    var template = [
      '<countdown-control
        flag="timerCtrl.interval"
        pause="timerCtrl.setInterval()"
        resume="timerCtrl.clearInterval()">',
      '</countdown>',
      '{{ timerCtrl.elapsed }} seconds has passed.'
    ].join('');

    // ------------
    // 
    return {
      template: getTemplate,
      link: linkFn,
      controller: controller,
      controllerAs: 'timerCtrl'
    }

    /** Start the countdown */
    function linkFn(scope, element, attributes, controller) {
      controller.setInterval();
    }

    /** Just a retarded API */
    function controller($scope) {
      var vm = this;

      vm.elapsed = 0;

      vm.clearInterval = clearInterval
      vm.setInterval = setInterval;
      vm.tick = tick;

      function setInterval() {
        vm.interval = setInterval.call(null, vm.tick);
      }

      function clearInterval() {
        vm.interval = clearInterval(vm.interval);
      }

      function tick() {
        vm.elapsed += 1;
      }
    }
  }