In this short article we will see how to write isNumber() in JavaScript.
We can code a IsNumber() function in JavaScript which will check if a value is a number or not. If the given value is a number it will return true , if it’s not it will return false.
Using Vanilla JavaScript
Code :
function isNumber(value){
return typeof value === 'number' && isFinite(value);
}
console.log(isNumber(22)) //true
console.log(isNumber('2')) // false
console.log(isNumber('hello')) //falseCode Explanation:
The isNumber(vlaue)function take a value as an argument from the user.
typeof : The typeof is a JavaScript operator to find the data type of the variable. The code typeof value === 'number' will return true if the type of the value is a number.
isFinite(value) : The isFinite() is a function that checks whether a number is a finite number. It will return false if the given value is positive or negative infinity, undefined or NaN (Not a Number), otherwise if its a number it will return true.
Using underscoreJs or Lodash
In underscorejs or Lodash JavaScript Library, we can check if a value is a number by using the _.isNumber() function.
Syntax:
_.isNumber( object )It will check if the given object argument is a number or not. If the given value is a number it will return true otherwise it will return false.
Related Topics:
Check If String Is A Number Or Not In JavaScript
