方法中this指向？

Question

  class BtnComponent{    constructor(){      this.state = {isLiked: false};    }    //改变文本    changeLikeText(){      var likeText = this.el.querySelector('.like-text');      this.state.isLiked = !this.state.isLiked;      likeText.innerHTML = this.state.isLiked ? '取消' : '点赞';    }      stringDom(string){      var div = document.createElement('div');        div.innerHTML = string;      return div;      }      render(){        this.el = this.stringDom('<button class = "like-button"><span class = "like-text">点赞</span><span>AA</span></button>');        this.el.addEventListener('click', this.changeLikeText.bind(this));        return this.el;      }  }这是一个点赞的插件，请问这句代码中后两个this分别指什么？为什么这么写？this.el.addEventListener('click', this.changeLikeText.bind(this))