Question

是否有任何方法可以检查给定类的实例？

如果有办法-是否还可以检索这些实例？

Answer 1

将每个实例添加到构造函数中的数组：

class Abc {
  constructor(arg) {
    this.arg = arg;
    Abc.instances.push(this);
  }
}
Abc.instances = [];

new Abc('qwe');
new Abc('rty');
console.log(Abc.instances);

Answer 2

class Instance{
  constructor(...args){
   //doSomething for init;
   Instance.HAS.add(this);
 }

}
Instance.HAS={
  instances:[],
add(instance){
this.instances.push(instance);
},
has(instance){
return this.instances.indexOf(instance)>-1;
},
all(){
 return this.instances;
}
};

let i1 = new Instance();
let i2 = new Instance();

console.info(Instance.HAS.all());
//VM1164:1 (2) [Instance, Instance]
console.info(Instance.HAS.has(i1));
//VM1245:1 true

检查是否存在任何类实例

2 个答案: