Hexadecimal to string in javascript

Question

function hex2a(hex) 
{
    var str = '';
    for (var i = 0; i < hex.length; i += 2)
        str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
    return str;
}     

This function is not working in chrome, but it is working fine in mozila. can anyone please help.

Thanks in advance

Answer 1

From your comments it appears you're calling

hex2a('000000000000000000000000000000314d464737');

and alerting the result.

Your problem is that you're building a string beginning with 0x00. This code is generally used as a string terminator for a null-terminated string.

Remove the 00 at start :

hex2a('314d464737');

You might fix your function like this to skip those null "character" :

function hex2a(hex) {
    var str = '';
    for (var i = 0; i < hex.length; i += 2) {
        var v = parseInt(hex.substr(i, 2), 16);
        if (v) str += String.fromCharCode(v);
    }
    return str;
}  

Note that your string full of 0x00 still might be used in other contexts but Chrome can't alert it. You shouldn't use this kind of strings.

Answer 2

you need convert every 2 digit of hex '314d464737'.match(/.{1,2}/g) -> [31,4d,46,47,37]

function a2hex(text){
    return [...text].map(x => 
    x.codePointAt()
     .toString(16)
     .padStart(2,"0")
   ).join('')
}
function hex2a(text){
    return String
     .fromCharCode(...text.match(/.{1,2}/g)
     .map(e => 
       parseInt(e, 16))
     )
}

var a = a2hex("hello")
var b = hex2a(a)
console.log(a) // 68656c6c6f
console.log(b) // hello