Javascript: Unicode string to hex

Remember that a JavaScript code unit is 16 bits wide. Therefore the hex string form will be 4 digits per code unit.

usage:

var str = "\u6f22\u5b57"; // "\u6f22\u5b57" === "漢字"alert(str.hexEncode().hexDecode());

String to hex form:

String.prototype.hexEncode = function(){    var hex, i;    var result = "";    for (i=0; i<this.length; i++) {        hex = this.charCodeAt(i).toString(16);        result += ("000"+hex).slice(-4);    }    return result}

Back again:

String.prototype.hexDecode = function(){    var j;    var hexes = this.match(/.{1,4}/g) || [];    var back = "";    for(j = 0; j<hexes.length; j++) {        back += String.fromCharCode(parseInt(hexes[j], 16));    }    return back;}

Here is a tweak of McDowell's algorithm that doesn't pad the result:

  function toHex(str) {    var result = '';    for (var i=0; i<str.length; i++) {      result += str.charCodeAt(i).toString(16);    }    return result;  }

It depends on what encoding you use. If you want to convert utf-8 encoded hex to string, use this:

function fromHex(hex,str){  try{    str = decodeURIComponent(hex.replace(/(..)/g,'%$1'))  }  catch(e){    str = hex    console.log('invalid hex input: ' + hex)  }  return str}

For the other direction use this:

function toHex(str,hex){  try{    hex = unescape(encodeURIComponent(str))    .split('').map(function(v){      return v.charCodeAt(0).toString(16)    }).join('')  }  catch(e){    hex = str    console.log('invalid text input: ' + str)  }  return hex}