Method getAttribute

src/core/a-mixin.js:91–94

* If `attr` is a component, then grab pre-parsed value from the cache. * Else do a normal getAttribute.

(attr)

   * Else do a normal getAttribute.
   */
  getAttribute (attr) {
    return this.componentCache[attr] ||
      window.HTMLElement.prototype.getAttribute.call(this, attr);
  }

  /**
   * Parse and cache every component defined on the mixin.