Javascript \x escaping

Question

I've seen a few other programs that have something like this:

var string = '\x32\x20\x60\x78\x6e\x7a\x9c\x89';

And I had to try to fiddle with the numbers and letters, to find the text I wanted to display.
I'm wondering if there is a function to find the \x escape of a string, like string.toUpperCase() in JS. I'm using processingJS, but it will be okay for me to use other programming languages to find the ASCII for \x.

Those programs could (and should) just have used ```var string = '2 `xnz\x9c\x89';```, and nothing would have been different. — Bergi, Dec 03 '15 at 02:15
That is true, But I wasn't used to this until now, I usually just type the characters. — HarryJamesPotter27, Dec 03 '15 at 13:09

score 14 · Accepted Answer · edited Oct 23 '20 at 12:54

If you have a string that you want escaped, you can use String.prototype.charCodeAt()

If you have the code with escapes, you can just evaluate them to get the original string. If it's a string with literal escapes, you can use String.fromCharCode()

If you have '\x32\x20\x60\x78\x6e\x7a\x9c\x89' and want "2 `xnz" then
```
  '\x32\x20\x60\x78\x6e\x7a\x9c\x89' == "2 `xnz"
```
If you have '\\x32\\x20\\x60\\x78\\x6e\\x7a\\x9c\\x89' which is a literal string with the value \x32\x20\x60\x78\x6e\x7a\x9c\x89 then you can parse it by passing the decimal value of each pair of hex digits to String.prototype.fromCharCode()
```
  '\\x32\\x20\\x60\\x78\\x6e\\x7a\\x9c\\x89'.replace(/\\x([0-9a-f]{2})/ig, function(_, pair) {
    return String.fromCharCode(parseInt(pair, 16));
  })
```
Alternatively, eval is an option if you can be sure of the safety of the input and performance isn't important¹.
```
  eval('"\\x32\\x20\\x60\\x78\\x6e\\x7a\\x9c\\x89"')
```
^{Note the " nested in the ' surrounding the input string.}

If you know it's a program, and it's from a trusted source, you can eval the string directly, which won't give you the ASCII, but will execute the program itself.
```
  eval('\\x32\\x20\\x60\\x78\\x6e\\x7a\\x9c\\x89')
```
^{Note that the input you provided is not a program and the eval call fails.}

If you have "2 `xnz" and want '\x32\x20\x60\x78\x6e\x7a\x9c\x89' then

  "2 `xnz".split('').map(function(e) {
    return '\\x' + e.charCodeAt(0).toString(16);
  }).join('')

Thank you! I'll try it out. – HarryJamesPotter27 Dec 03 '15 at 13:11 — HarryJamesPotter27, Dec 03 '15 at 13:11

Javascript \x escaping

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