Node.js 在原型中更改 Number 对象值 [英] Node.js change Number object value inside prototype

问题描述

我想给 Number 类型添加一个新方法，然后用它来改变它自己的值.我写下面的代码:

I want to add a new method to Number type, and then use it to change its own value. I write below code:

Number.prototype.maxx = function(N) {
  if (N > this.valueOf()) {
    //change this number value to N 
  }
}

var X = 5;
X.maxx(7);
console.log(X); //expect to show 7

我尝试使用以下代码来更改值

I try something like below codes to change the value

this = N;

或

this.valueOf(N);

或

this.value = N; //of course number do not have any property named 'value'. but I just try it!

但它们都不起作用.

你能不能给我一些提示来做这件事.谢谢，

Could you please give me some hint to do this. Thanks,

推荐答案

Number.prototype.maxx = function(N) {
  if (N > this.valueOf()) {
    return N;
  } else {
    return this.valueOf(); 
  }
}

var X = 5;
X = X.maxx(4);

我想在这里强调的一件事是，当您调用 X.maxx 时，您无法更改它的值.相反，您必须将从方法返回的值重新分配给 X.

One thing that I would like to highlight over here is when you call X.maxx you cannot change the value of this. Instead, you will have to re-assign the value being returned back from the method to X.

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