memoize_ex.js

let pollDelay = 750;
function () {
      this.m = _.memoize(function (time) {
          return time + pollDelay;
      });

      this.t = 0;
      this.rm = _.noop;

      this.getEvents = function () {
          var t = this.t;
          this.rm = _.memoize(function () {
              return t;
          });

          this.t = this.m(new Date().getTime());
          console.log(this.t - this.rm(), this.t - this.rm() === pollDelay)

          $http.get('this.apiUrl', {}).then(function (res) {
              
          });
      };
}