Javascript以不同的方式声明数字？ [英] Javascript declaring number in different ways?

问题描述

var a = 1;
var b = Number(1);
var c = new Number(1);

我想知道这三个陈述之间有什么区别。
我理解第一和第二个陈述是相同的，因为如果（a === b）给出 true ，但第三个将创建一个类型为number的对象。

I was wondering what is the difference between these three statements. I understand that first and second statements are same, as if(a===b) gives true, but the third one will create a object of type number.

我想知道的是这些方法是如何不同的，以及任何方法一个人会优先于另一个？

What I want to know is how these methods are different, and any advantages one will give over the other?

推荐答案

像 1 这样的值是原始的，而不是对象。 JavaScript通常会在必要时将数字提升为 Number 对象。很少有理由明确地构建一个，并且肯定没有特别的优势。也没有理由像 Number（1），尽管 Number 构造函数是强制执行的几种方法之一价值是一个数字。

A value like 1 is a primitive, not an object. JavaScript will generally promote numbers to Number objects when necessary. There's rarely a reason to explicitly construct one, and there's certainly no particular "advantage". There's also no reason for something like Number(1), though the Number constructor is one of several ways of coercing a value to be a number.

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