instanceof.ts

/**
 * @description instanceof
 * @author tangc1
 * @date 2022-04-23 14:38:54
*/

exportfunctionmyInstanceof(instance: any,origin: any): boolean{
if(instance==null)returnfalse// null undefined

consttype=typeofinstance
// 值类型
if(type!=='object'&&type!=='function')returnfalse

lettempInstance=instance// 防止修改instance
while(tempInstance){
if(tempInstance.__proto__===origin.prototype){
// 匹配上
returntrue
}
tempInstance=tempInstance.__proto__// 顺着原型链往上找
}
returnfalse
}


console.info(myInstanceof({},Object));
console.info(myInstanceof([],Object));
console.info(myInstanceof([],Array));
console.info(myInstanceof('abc',String));