js重写prototype.call，但是为什么出现“RangeError: Maximum call stack size returned”

Question

Function.prototype.call = function(point,...arg){
    console.log('ok');
    const key = Symbol('key')
    point[key] = this
    const data = point[key](...arg)
    delete point[key]
    return data
}
function fn(a,b){
    this.sum = a+b
    return a + b
}
const obj = {}
const data = fn.call(obj,3,4)
console.log(data);
console.log(obj);

node:internal/bootstrap/switches/is_main_thread:149
  if (stdout) return stdout;
  ^

RangeError: Maximum call stack size exceeded
    at process.getStdout [as stdout] (node:internal/bootstrap/switches/is_main_thread:149:3)  
    at console.get (node:internal/console/constructor:214:42)
    at console.value (node:internal/console/constructor:340:50)
    at console.log (node:internal/console/constructor:379:61)
    at Function.call (C:\Users\xyk\Desktop\my study\nodejs\node.js中级\23重写call函数.js:2:13)
    at new WriteStream (node:tty:96:14)
    at createWritableStdioStream (node:internal/bootstrap/switches/is_main_thread:53:16)      
    at process.getStdout [as stdout] (node:internal/bootstrap/switches/is_main_thread:150:12) 
    at console.get (node:internal/console/constructor:214:42)
    at console.value (node:internal/console/constructor:340:50)

Node.js v20.12.1

但是如果将“prototype.call”改为“prototype.Mycall”，就不会出现这个问题了

Function.prototype.Mycall = function(point,...arg){
    console.log('ok');
    const key = Symbol('key')
    point[key] = this
    const data = point[key](...arg)
    delete point[key]
    return data
}
function fn(a,b){
    this.sum = a+b
    return a + b
}
const obj = {}
const data = fn.Mycall(obj,3,4)
console.log(data);
console.log(obj);

ok
7
{ sum: 7 }

这个问题真让我困惑

如果我删除“console.log()”，问题就会消失。但我想说，对于“prototype.Mycall”的情况，即使有“console.log()”，也不会报错

Answer 1

nodejs

console.log

实现使用

.call()

。您的

Function.prototype.call

实现使用

console.log()

。这意味着相互递归，并且由于没有基本情况而导致堆栈溢出。

所以：不要搞乱内置函数！