How to Trim Leading Zeros from a String in JavaScript
We recommend using regular expressions and the string replace() method to remove leading zeros from a string.
let x = '0042';
x = x.replace(/^0+/, '');
x; // '42';
typeof x; // 'string'Converting to a Number
You may have seen code that uses x * 1 or +x to remove leading zeros from a string.
This approach works for basic cases, with the key difference that you end up with a number rather than a string.
let x = '0042';
x = parseInt(x);
x; // 42
typeof x; // 'number'
let y = '007';
y = +y;
y; // 7
typeof y; // 'number'However, things get tricky with strings that contain hex, octal, and binary literals as shown below.
let x = '0xFF';
x = +x;
x; // 255Whether this behavior is correct depends on your use case.
However, if you want to treat x as a string and remove leading zeros, the correct output here would be 'xFF'.
In that case, using + or parseInt() won't work.
You can tell parseInt() to always use base 10 and avoid parsing strings that start with 0x as hexadecimal numbers, but then you end up with a 0.
let x = '0xFF';
x = parseInt(x, 10);
x; // 0, because `parseInt()` parses as much as it can
typeof x; // 'number'