• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

The Programming Expert

Solving All of Your Programming Headaches

  • HTML
  • JavaScript
  • jQuery
  • PHP
  • Python
  • SAS
  • Ruby
  • About
You are here: Home / JavaScript / Using JavaScript to Add Leading Zeros

Using JavaScript to Add Leading Zeros

June 9, 2022 Leave a Comment

In JavaScript, we can convert an integer to a string and add leading zeros to it by making use of the addition operator (+). Let’s say we have the integer 456 and we want to add 3 zeros to the front of it. Here is the code to do this:

var num = 456;
var convertedNumber = "000" + num;

console.log(convertedNumber);

#Output:
000456

By using the addition operator + between a string and a number like we did above, we will concatenate the number to a string. So we do not need to convert the integer to a string using something like the toString() method. We just need the addition operator + and that’s it.

Let’s put our code in a function so we can add as many leading zeros as we want to any number. To make it so we add as many zeros as the user tells us, we need to make use of the repeat() method.

function addLeadingZeros(number,numZeros){
  var numberOfZeros = "0".repeat(numZeros);
  return (numberOfZeros + number);
};

And now lets see our function in action with an example:

function addLeadingZeros(number,numZeros){
  var numberOfZeros = "0".repeat(numZeros);
  return (numberOfZeros + number);
};

console.log(addLeadingZeros(456,3));

#Output:
000456

When working with integers, the ability to modify the values of the variables easily is valuable.

One such situation is when you have an integer and want to convert it to a string and add leading zeros to the string.

Many times, when you are working with data that has an ID or a record number, that is represented by a number, you need to add leading zeros to maintain data integrity.

To add leading zeros to a string in JavaScript, the easiest way is with the addition operator +.

Let’s show our function one more time and add some more examples to see it in action.

function addLeadingZeros(number,numZeros){
  var numberOfZeros = "0".repeat(numZeros);
  return (numberOfZeros + number);
};

console.log(addLeadingZeros(123,3));
console.log(addLeadingZeros(987650987,6));
console.log(addLeadingZeros(123,0));
console.log(addLeadingZeros("00111",2));
console.log(addLeadingZeros(90809281,10));

#Output:
000123
000000987650987
123
0000111
000000000090809281

Hopefully this article has been useful for you to learn how to use JavaScript to add leading zeros.

Other Articles You'll Also Like:

  • 1.  Using JavaScript to Convert String to Boolean
  • 2.  Convert a Set to Array in JavaScript
  • 3.  Using JavaScript to Round to 4 Decimal Places
  • 4.  Using JavaScript to Get URL Hash
  • 5.  Remove String From Array in JavaScript
  • 6.  Using Javascript to Remove Class from Element
  • 7.  parseFloat JavaScript – How to use the JavaScript parseFloat() method
  • 8.  JavaScript Infinite Loop
  • 9.  JavaScript Check if Attribute Exists in HTML Element
  • 10.  JavaScript Coin Flip – How to Simulate Flipping a Coin in JavaScript

About The Programming Expert

The Programming Expert is a compilation of a programmer’s findings in the world of software development, website creation, and automation of processes.

Programming allows us to create amazing applications which make our work more efficient, repeatable and accurate.

At the end of the day, we want to be able to just push a button and let the code do it’s magic.

You can read more about us on our about page.

Reader Interactions

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

About The Programming Expert

the programming expert main image

Welcome to The Programming Expert. We are a group of US-based programming professionals who have helped companies build, maintain, and improve everything from simple websites to large-scale projects.

We built The Programming Expert to help you solve your programming problems with useful coding methods and functions in various programming languages.

Search

Learn Coding from Experts on Udemy

Looking to boost your skills and learn how to become a programming expert?

Check out the links below to view Udemy courses for learning to program in the following languages:

Copyright © 2023 · The Programming Expert · About · Privacy Policy