Question

Are there any equivalent JavaScript functions for Python’s urllib.parse.quote() and urllib.parse.unquote()?

The closest I’ve come across are encodeURI()/encodeURIComponent() and escape() (and their corresponding un-encoding functions), but they don’t encode/decode the same set of special characters as far as I can tell.

Answer 1

OK, I think I’m going to go with a hybrid custom set of functions:

Encode: Use encodeURIComponent(), then put slashes back in.
Decode: Decode any %hex values found.

Here’s a more complete variant of what I ended up using (it handles Unicode properly, too):

function quoteUrl(url, safe) {
    if (typeof(safe) !== 'string') {
        safe = '/';    // Don't escape slashes by default
    }

    url = encodeURIComponent(url);

    // Unescape characters that were in the safe list
    toUnencode = [  ];
    for (var i = safe.length - 1; i >= 0; --i) {
        var encoded = encodeURIComponent(safe[i]);
        if (encoded !== safe.charAt(i)) {    // Ignore safe char if it wasn't escaped
            toUnencode.push(encoded);
        }
    }

    url = url.replace(new RegExp(toUnencode.join('|'), 'ig'), decodeURIComponent);

    return url;
}


var unquoteUrl = decodeURIComponent;    // Make alias to have symmetric function names

Note that if you don’t need “safe” characters when encoding ('/' by default in Python), then you can just use the built-in encodeURIComponent() and decodeURIComponent() functions directly.

Also, if there are Unicode characters (i.e. characters with codepoint >= 128) in the string, then to maintain compatibility with JavaScript’s encodeURIComponent(), the Python quote_url() would have to be:

def quote_url(url, safe):
    """URL-encodes a string (either str (i.e. ASCII) or unicode);
    uses de-facto UTF-8 encoding to handle Unicode codepoints in given string.
    """
    return urllib.quote(unicode(url).encode('utf-8'), safe)

And unquote_url() would be:

def unquote_url(url):
    """Decodes a URL that was encoded using quote_url.
    Returns a unicode instance.
    """
    return urllib.unquote(url).decode('utf-8')