Lodash isNumber function has an extra condition to check if value is number. I'm not sure why is that required and in what case it is not enough to use just typeof value == 'number'
function isNumber(value) {
return typeof value == 'number' ||
(isObjectLike(value) && getTag(value) == '[object Number]')
}
https://github.com/lodash/lodash/blob/aa1d7d870d9cf84842ee23ff485fd24abf0ed3d1/isNumber.js
From your link:
Checks if
valueis classified as aNumberprimitive or object.
var n = new Number(3);
console.log(typeof n); // "object"
console.log(_.isNumber(n)); // true
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.
While the Number() function will create a number primitive, the Number() constructor will create a Number object:
typeof Number(0) // 'number'
typeof new Number(0) // 'object'
Lodash checks for both cases.