Encode String to HEX

Question

i have my function to convert string to hex:

function encode(str){
    str = encodeURIComponent(str).split('%').join('');
    return str.toLowerCase();
}

example:

守护村子

alert(encode('守护村子'));

the output would be:

e5ae88e68aa4e69d91e5ad90

It works on Chinese characters. But when i do it with English letters

alert(encode('Hello World'));

it outputs:

hello20world

I have tried this for converting string to hex:

function String2Hex(tmp) {
    var str = '';
    for(var i = 0; i < tmp.length; i++) {
        str += tmp[i].charCodeAt(0).toString(16);
    }
    return str;
}

then tried it on the Chinese characters above, but it outputs the UTF-8 HEX:

5b8862a467515b50

not the ANSI Hex:

e5ae88e68aa4e69d91e5ad90

I also have searched converting UFT8 to ANSI but no luck. Anyone could help me? Thanks!

check out this [answer](http://stackoverflow.com/questions/21647928/javascript-unicode-string-to-hex). I think it might be what you're looking for. — nlloyd, Apr 15 '16 at 02:17
Thanks but it is not the answer, it is similar to the `String2Hex` function above, that gives the utf8 hex code, not ansi hex code. But thanks anyway. — John Pangilinan, Apr 15 '16 at 02:19
Try converting the text to latin1 using `tmp = unescape(encodeURIComponent(str))` — B. Colin Tim, Jul 06 '17 at 05:42
Possible duplicate of [Javascript: Unicode string to hex](https://stackoverflow.com/questions/21647928/javascript-unicode-string-to-hex) — Lukas Eder, Mar 06 '18 at 13:33

Daniel Earwicker · Answer 1 · 2020-10-11T23:04:22.467

25

As a self-contained solution in functional style, you can encode with:

plain.split("")
     .map(c => c.charCodeAt(0).toString(16).padStart(2, "0"))
     .join("");

The split on an empty string produces an array with one character (or rather, one UTF-16 codepoint) in each element. Then we can map each to a HEX string of the character code.

Then to decode:

hex.split(/(\w\w)/g)
   .filter(p => !!p)
   .map(c => String.fromCharCode(parseInt(c, 16)))
   .join("")

This time the regex passed to split captures groups of two characters, but this form of split will intersperse them with empty strings (the stuff "between" the captured groups, which is nothing!). So filter is used to remove the empty strings. Then map decodes each character.

edited Oct 11 '20 at 23:04

answered Feb 27 '20 at 14:39

Daniel Earwicker

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@rumpel true! I’ve added a `padStart`. – Daniel Earwicker Oct 11 '20 at 23:09
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This should be the accepted answer, since it works in modern browsers and node and does not require additional libraries. – Jankapunkt Apr 06 '21 at 14:37
Hmm... "fromCharCode" returns anything in between 0 and 65535, and to encode it properly you need 4 hex characters, not 2, right? Don't think this answer will work for any strings containing non-ASCII characters... – stillwaiting Jan 28 '23 at 13:30

score 23 · Answer 2 · edited Aug 13 '22 at 20:42

23

On Node.js, you can do:

const myString = "This is my string to be encoded/decoded";
const encoded = Buffer.from(myString).toString('hex'); // encoded == 54686973206973206d7920737472696e6720746f20626520656e636f6465642f6465636f646564
const decoded = Buffer.from(encoded, 'hex').toString(); // decoded == "This is my string to be encoded/decoded"

edited Aug 13 '22 at 20:42

Roj

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answered Aug 01 '18 at 02:33

Cassio

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FYI: The `Buffer` class is not standardized by any standards body I know of, including ECMA. It *is* offered by Node.js, however, and does what you'd think it does. – Armen Michaeli Nov 17 '18 at 13:23
6

**Doesn't work in browsers.** Not only isn't it standardized like amn says, but also it just doesn't exist, it's only a Node.js thing unfortunately. This means it doesn't answer the question because, obviously, alert() as OP used in the question doesn't make sense in Node.js, they clearly meant for this to work in a browser. But hopefully it still helps others that want to use this in server-side code... – Luc Mar 19 '21 at 13:10

score 2 · Accepted Answer · edited Aug 02 '22 at 02:18

2

I solved it by downloading utf8.js

https://github.com/mathiasbynens/utf8.js

then using the String2Hex function from above:

alert(String2Hex(utf8.encode('守护村子')));

It gives me the output I want:

e5ae88e68aa4e69d91e5ad90

edited Aug 02 '22 at 02:18

Pang

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answered Apr 15 '16 at 02:30

John Pangilinan

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Anyone looking at this question like me should also consider the following: http://stackoverflow.com/questions/32965971/javascript-charcodeat-different-values-in-jsfiddle-and-in-local-file – haakym Mar 23 '17 at 08:44
anyone looking for answer without third part can refer [http://stackoverflow.com/questions/21647928/javascript-unicode-string-to-hex](http://stackoverflow.com/questions/21647928/javascript-unicode-string-to-hex) – nbi Apr 10 '17 at 09:17
3

This answer isn't really self contained. It relies entirely on an external resource... – Lukas Eder Mar 06 '18 at 13:33

score 2 · Answer 4 · edited Aug 02 '22 at 02:19

2

This should work.

var str="some random string";
var result = "";
for (i=0; i<str.length; i++) {
    hex = str.charCodeAt(i).toString(16);
    result += ("000"+hex).slice(-4);
}

edited Aug 02 '22 at 02:19

Pang

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answered Aug 10 '17 at 07:19

hannad rehman

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score 1 · Answer 5 · edited Apr 07 '23 at 08:39

If you want to properly handle UTF8 strings you can try these:

function utf8ToHex(str) {
  return Array.from(str).map(c => 
    c.charCodeAt(0) < 128
      ? c.charCodeAt(0).toString(16)
      : encodeURIComponent(c).replace(/\%/g,'').toLowerCase()
  ).join('');
}

function hexToUtf8(hex) {
  return decodeURIComponent('%' + hex.match(/.{1,2}/g).join('%'));
}

Demo: https://jsfiddle.net/lyquix/k2tjbrvq/

score 0 · Answer 6 · answered Feb 13 '22 at 07:25

0

Another way to do it

function toHex(txt){
    const encoder = new TextEncoder();
    return Array
        .from(encoder.encode(txt))
        .map(b => b.toString(16).padStart(2, '0'))
        .join('')
}

answered Feb 13 '22 at 07:25

malkaby

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Encode String to HEX

6 Answers6

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