如何在 JavaScript 中将十六进制转换为 ASCII？

function hex2a(hexx) {
var hex = hexx.toString();//force conversion
var str = '';
for (var i = 0; i < hex.length; i += 2)
str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
return str;
}
hex2a('32343630'); // returns '2460'

For completeness sake the reverse function:

function a2hex(str) {
var arr = [];
for (var i = 0, l = str.length; i < l; i ++) {
var hex = Number(str.charCodeAt(i)).toString(16);
arr.push(hex);
}
return arr.join('');
}
a2hex('2460'); //returns 32343630

You can use this..

var asciiVal = "32343630".match(/.{1,2}/g).map(function(v){
return String.fromCharCode(parseInt(v, 16));
}).join('');
    

document.write(asciiVal);

Another way to do it (if you use Node.js):

var input  = '32343630';
const output = Buffer.from(input, 'hex');
log(input + " -> " + output);  // Result: 32343630 -> 2460

I've found that the above solution will not work if you have to deal with control characters like 02 (STX) or 03 (ETX), anything under 10 will be read as a single digit and throw off everything after. I ran into this problem trying to parse through serial communications. So, I first took the hex string received and put it in a buffer object then converted the hex string into an array of the strings like so:

buf = Buffer.from(data, 'hex');
l = Buffer.byteLength(buf,'hex');
for (i=0; i<l; i++){


char = buf.toString('hex', i, i+1);
msgArray.push(char);


}

Then .join it

message = msgArray.join('');

then I created a hexToAscii function just like in @Delan Azabani's answer above...

function hexToAscii(str){
hexString = str;
strOut = '';
for (x = 0; x < hexString.length; x += 2) {
strOut += String.fromCharCode(parseInt(hexString.substr(x, 2), 16));
}
return strOut;
}

then called the hexToAscii function on 'message'

message = hexToAscii(message);

This approach also allowed me to iterate through the array and slice into the different parts of the transmission using the control characters so I could then deal with only the part of the data I wanted. Hope this helps someone else!

I found a useful function present in web3 library.

var hexString = "0x1231ac"
string strValue = web3.toAscii(hexString)

Update: Newer version of web3 has this function in utils

The functions now resides in utils:

var hexString = "0x1231ac"
string strValue = web3.utils.hexToAscii(hexString)

An optimized version of the implementation of the reverse function proposed by @michieljoris (according to the comments of @Beterraba and @Mala):

function a2hex(str) {
var hex = '';
for (var i = 0, l = str.length; i < l; i++) {
var hexx = Number(str.charCodeAt(i)).toString(16);
hex += (hexx.length > 1 && hexx || '0' + hexx);
}
return hex;
}
alert(a2hex('2460')); // display 32343630

** for Hexa to String**

let input  = '32343630';

Note : let output = new Buffer(input, 'hex'); // this is deprecated

let buf = Buffer.from(input, "hex");
let data = buf.toString("utf8");