new this(...args)什么意思啊？

Question

下面代码什么意思啊class  A{  static instance(...args) {        this.i = this.i || new this(...args)        return this.i    }}this.i = this.i || new this(...args)完全看不懂啊，这里this.i是个什么鬼new this(...args)又是什么？

Answer 1

短路。等同於：

class A{

  static instance(...args) {

        if (this.i) this.i = this.i;

        else this.i = new this(...args);

        return this.i;

    }

}

new this(...args) is equal to new A(...args).