code: function Renderer(options = {}) {
      if (!(this instanceof Renderer)) {
          return new Renderer(options);
      }
      var o = (this.options = Object.assign({}, defaults, options));
  
      // custom handlebars instance
      this.handlebars = handlebars.create();
  
      // register global helpers/partials
      if (o.helpers) this.helper(o.helpers);
      if (o.partials) this.partial(o.partials);
  
      // enabling caching (via lru-cache)
      if (o.cache) {
          this.cache = new Cache({ max: 100 });
      }
  }
docs: A Handlebars rendering abstraction class. Made a constructor to allow
  sub-classing and customization.
  
  @constructor
  @param {Object} options