gistfile1.js

/**
 * == Can it be done? ==
 *
 * I want to get from keyIdentifier to actual character, eg from U+0023
 * to \u0023 - which if dropped in a string is the # character: 
 * http://jsconsole.com/?%22\u0023%22
 *
 * The problem is the starting point, and I know I can do it using an 
 * eval, but eval is evil, right? So how can I do it?
 *
 * Can you solve this?  
 * - @rem
 */

/**
  * Taken from http://rishida.net/tools/conversion/.
  */

    function hex2char ( hex ) {
        // converts a single hex number to a character
        // note that no checking is performed to ensure that this is just a hex number, eg. no spaces etc
        // hex: string, the hex codepoint to be converted
        var result = '';
        var n = parseInt(hex, 16);
        if (n <= 0xFFFF) {
            result += String.fromCharCode(n);
        } else if (n <= 0x10FFFF) {
            n -= 0x10000
            result += String.fromCharCode(0xD800 | (n >> 10)) + String.fromCharCode(0xDC00 | (n & 0x3FF));
        } else {
            result += 'hex2Char error: Code point out of range: '+dec2hex(n);
        }
        return result;
    }

    function convertUnicode2Char (str) { 
        // converts a string containing U+... escapes to a string of characters
        // str: string, the input

        // first convert the 6 digit escapes to characters
        str = str.replace(/[Uu]\+10([A-Fa-f0-9]{4})/g, function(matchstr, parens) {
            return hex2char('10'+parens);
        }); 
        // next convert up to 5 digit escapes to characters
        str = str.replace(/[Uu]\+([A-Fa-f0-9]{1,5})/g, function(matchstr, parens) {
            return hex2char(parens);
        }); 
        return str;
    }
        
    var code = "U+0023";
    convertUnicode2Char(code); // #