javascript - 为什么 lodash .isNumber 函数比 typeof value == 'number' 更复杂

Question

洛达什 isNumber函数有一个额外的条件来检查值是否为数字。我不确定为什么需要这样做，在什么情况下仅使用 typeof value == 'number' 是不够的

function isNumber(value) {
  return typeof value == 'number' ||
    (isObjectLike(value) && getTag(value) == '[object Number]')
}

https://github.com/lodash/lodash/blob/aa1d7d870d9cf84842ee23ff485fd24abf0ed3d1/isNumber.js

Answer 1

从您的链接:

Checks if value is classified as a Number primitive or object.

var n = new Number(3);
console.log(typeof n); // "object"
console.log(_.isNumber(n)); // true

MDN - Number :

The Number JavaScript object is a wrapper object allowing you to work with numerical values. A Number object is created using the Number() constructor. A primitive type object number is created using the Number() function.