code: function extender (d, b) {
    _.each(b, (p) => {
      /* istanbul ignore if */
      if (Object.prototype.hasOwnProperty.call(b, p)) {
        d[p] = b[p];
      }
    });
  
    function Factory () {
      this.constructor = d;
    }
  
    /* istanbul ignore next */
    d.prototype = b === null ? Object.create(b) : (Factory.prototype = b.prototype, new Factory());
  }
docs: /* Files 
  Extends
  
  Standard extender function taken from
  Babel/TypeScript compiler.
  
  @type {*}
  @private