How to Get Hex Integer from a String in Js?

Question

I would like to convert this: "#FFFFFF" to this: 0xFFFFFF. How is it possible without using eval?

Thanks in advance,

Accepted Answer

Strip off the "#" and use parseInt().

var hex = parseInt(str.replace(/^#/, ''), 16);

Then, if you want to see it in hex, you can use .toString():

console.log(hex.toString(16));

Answer 2

Use this code:

var resultP = document.getElementById('result');
var btn = document.querySelector('button');
var input = document.querySelector('input');
function convert(hex) {
  return Number(`0x${hex.substr(1)}`);
}
btn.addEventListener('click', () => {
  resultP.innerHTML = convert(input.value);
})

* {
  font-family: Arial;
}

<!DOCTYPE html>
<html>
  <head>
    <title>Hex code to hex integer</title>
    <meta charset="UTF-8" />
  </head>
  <body>
    <input type="text" maxlength="7" />
    <button>Done</button>
    <br />
    Result:
    <p id="result"></p>
  </body>
</html>

Answer 3

You could try this code:

function hex2num(hexcode){ return Number(  '0x' + hexcode.split(/[^0-9a-fA-F]+/).join('')  ) }

This function will strip out all characters that are not numbers between 0-9 or alphabetical characters between A-F before trying to parse the input. The output is a number, because 0x009 === 9 in JS.

This solution works when dealing with numbers that are less than the MAX SAFE INTEGER (9007199254740991) but if the hex code equates to a number larger than that you will probably need to use a different solution.

Expected Usage:

hex2num('#0000FF') === 255 // true

hex2num('#FFFFFF') === 16777215 // true

hex2num('0x000000000001') === 1 // true

hex2num('0L0L4') === 4 // true

How to Get Hex Integer from a String in Js?

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How to Get Hex Integer from a String in Js?

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