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js class this在new与静态引用时所指不同

 1 year ago
source link: https://qidizi.github.io/js-class-this/
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js class this在new与静态引用时所指不同

this在这里的表现也跟func样跟着谁说叫谁老板的，与function.call(“this”概念一样。

简单的一个类

class a{
static a = "static-a";
 b = "ins-b";

constructor(){
console.log('new',this.a,this.b,this);
}

static fn(){
console.log('static',this.a,this.b,this);
}

}
  • new用法new a();时输出如后：new undefined ins-b a {b: "ins-b"}，选择性失明，static的东西与被抛弃了；
  • static用法：a.fn();，输出结果如下：
static static-a undefined class a{
static a = "static-a";
 b = "ins-b";

constructor(){
console.log('new',this.a,this.b,this);
}

static fn(){
console.log('static',this.a,this.b,this);
}

}

同样，new的东西被选择性抛弃；

ok，通过上面2个例子，我们可以明确了解到，this，就是指向当前这个使用的对象如new出来的实例，或是static

发表于 2019.07.16 14:50:24

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