How to use typeof number in JavaScript?

Table of Contents

• Introduction
• How to Use typeof for Numbers in JavaScript
  • Syntax:
  • Example:
• Checking for Numbers Using typeof
  • Example 1: Basic Number Check
  • Example 2: Handling Non-Numeric Values
  • Example 3: NaN and Infinity
• Practical Use Case: Type Validation for Numeric Input
  • Example: Validating User Input
• Conclusion

Introduction

In JavaScript, the typeof operator is used to determine the type of a variable or expression. When used with numbers, it returns the string "number". This feature is commonly used to check if a variable holds a numeric value, ensuring type safety and avoiding runtime errors during mathematical operations.

How to Use typeof for Numbers in JavaScript

The typeof operator can easily check whether a variable is a number by comparing its result to the string "number".

Syntax:

In this case, operand is the variable or value that you want to check.

Example:

Checking for Numbers Using typeof

Example 1: Basic Number Check

If the variable holds a numeric value, typeof will return "number". This works for both integers and floating-point numbers.

Example 2: Handling Non-Numeric Values

typeof will return something other than "number" if the value is not a number. This helps avoid errors when performing mathematical operations on non-number types.

Example 3: NaN and Infinity

In JavaScript, both NaN (Not-a-Number) and Infinity are treated as numbers.

Practical Use Case: Type Validation for Numeric Input

Example: Validating User Input

You can use typeof to ensure that user input is a number before performing operations, like a calculation, to avoid runtime errors.

Conclusion

Using the typeof operator in JavaScript allows you to easily check whether a value is a number, ensuring safer and more predictable code. By incorporating this check, you can prevent common bugs and type-related issues when working with numbers in JavaScript.