JavaScript Regex to remove leading zeroes from numbers?

In this article, we will learn to remove leading zeroes from numbers in JavaScript using Regex. When working with numeric strings in JavaScript, it's common to encounter unwanted leading zeroes. These zeroes can cause issues when parsing numbers, formatting data, or displaying user-friendly outputs.

Why Remove Leading Zeroes in JavaScript?

Leading zeroes can lead to inconsistencies in numeric string representation. For instance ?

• When parsing numbers, leading zeroes might result in incorrect interpretations.
  
• Displaying numbers with leading zeroes can confuse users or look unprofessional.
  
• Clean strings are essential for accurate mathematical operations and data storage.

By removing leading zeroes, you ensure uniformity and maintain clean data structures.

Using Regex with replace()

The replace() method is a simple and direct way to remove leading zeroes from strings. It searches for a specific pattern (in this case, leading zeroes) and replaces them with an empty string.

Following is the regex pattern we will use to remove leading zeroes from numbers ?

• Regex Pattern: /^0+/
  
  • ^: Asserts the start of the string.
    
  • 0+: Matches one or more consecutive zeroes.
• replace(/^0+/, ""): Replaces the matched leading zeroes with an empty string.

To remove leading zeros, use Regex in replace() method as in the below syntax ?

yourStringValue.replace(/\D|^0+/g, ""));

Example

Below is an example of removing leading zeroes from numbers using the replace() method ?

var theValue1="5001000";
var theValue2="100000005";
var theValue3="05000001";
var theValue4="00000000006456";
console.log(theValue1.replace(/\D|^0+/g, ""));
console.log(theValue2.replace(/\D|^0+/g, ""));
console.log(theValue3.replace(/\D|^0+/g, ""));
console.log(theValue4.replace(/\D|^0+/g, ""));

Output

5001000
100000005
5000001
6456

Using Regex with match()

The match() method provides an alternative by extracting the string part that doesn't include leading zeroes. Instead of replacing zeroes, it identifies the numeric part of the string.

Following is the regex pattern we will use to remove leading zeroes from numbers ?

• Regex Pattern: /^0*(\d+)/
  
  • ^: Matches the start of the string.
    
  • 0*: Matches zero or more leading zeroes.
    
  • (\d+): Captures one or more digits after the leading zeroes.
• Using match(): Returns an array where:
  
  • result[0]: The full match.
    
  • result[1]: The captured digits without leading zeroes.

Match leading zeroes and capture the rest ?

let result = value.match(/^0*(\d+)/);

Example 

Below is an example of removing leading zeroes from numbers using the match() method?

var theValue1 = "5001000";
var theValue2 = "100000005";
var theValue3 = "05000001";
var theValue4 = "00000000006456";

function removeLeadingZeroes(value) {
  let result = value.match(/^0*(\d+)/); // Match leading zeroes and capture the rest
  return result ? result[1] : "";      // Return the captured group or an empty string
}

// Test Cases
console.log(removeLeadingZeroes(theValue1)); 
console.log(removeLeadingZeroes(theValue2)); 
console.log(removeLeadingZeroes(theValue3)); 
console.log(removeLeadingZeroes(theValue4));

Output

5001000
100000005
5000001
6456

Comparison Table