How to remove the first character from a string if it is 0 in JavaScript?

General Discussions
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1

I want to delete the first character of a string if it’s a 0. The 0 could appear multiple times at the start.

Is there a simple function to check the first character and remove it if it’s 0? I’m currently using the slice() function, but it feels a bit awkward.

What’s the best way to JavaScript remove first character from string if it’s 0?

2

The simplest and most efficient approach is to use a regular expression with the replace() function.

This allows you to remove leading 0s without the need for awkward slicing.

Here’s how you can do it:

function removeLeadingZero(str) {
  return str.replace(/^0+/, '');  // Removes all leading zeros
}

console.log(removeLeadingZero("000123"));  // Outputs: "123"

Why this works? The ^0+ regex matches one or more zeros at the start of the string (^ indicates the start). This solution is clean and does the job in one line.

3

If you prefer to stick with slice() but want to make the operation more explicit, you can use a loop to iteratively remove the leading 0s.

This is a more manual approach but can be useful if you need fine control over the string.

function removeLeadingZero(str) {
  while (str.charAt(0) === '0') {
    str = str.slice(1);
  }
  return str;
}

This approach keeps the slice() function but ensures you handle multiple leading zeros in a more controlled manner.

4

If you’re feeling adventurous and want to ensure only the first occurrence of 0 is removed (for cases like “01230”), you can use a custom function with replace():

function removeLeadingZero(str) {
  return str.replace(/^0/, '');  // Removes only the first leading zero
}

console.log(removeLeadingZero("01230"));  // Outputs: "1230"

This version handles only the first leading zero and leaves the others intact. It’s great for cases where you want to remove a specific zero but not all leading zeros.