String.fromCodePoint()

String.fromCodePoint(42); // "*" String.fromCodePoint(65, 90); // "AZ" String.fromCodePoint(0x404); // "\u0404" String.fromCodePoint(0x2f804); // "\uD87E\uDC04" String.fromCodePoint(194564); // "\uD87E\uDC04" String.fromCodePoint(0x1d306, 0x61, 0x1d307); // "\uD834\uDF06a\uD834\uDF07" String.fromCodePoint("_"); // RangeError String.fromCodePoint(Infinity); // RangeError String.fromCodePoint(-1); // RangeError String.fromCodePoint(3.14); // RangeError String.fromCodePoint(3e-2); // RangeError String.fromCodePoint(NaN); // RangeError 

// String.fromCharCode() alone cannot get the character at such a high code point // The following, on the other hand, can return a 4-byte character as well as the // usual 2-byte ones (i.e., it can return a single character which actually has // a string length of 2 instead of 1!) console.log(String.fromCodePoint(0x2f804)); // or 194564 in decimal 

/*! http://mths.be/fromcodepoint v0.1.0 by @mathias */ if (!String.fromCodePoint) { (function () { var defineProperty = (function () { // IE 8 only supports `Object.defineProperty` on DOM elements try { var object = {}; var $defineProperty = Object.defineProperty; var result = $defineProperty(object, object, object) && $defineProperty; } catch (error) {} return result; })(); var stringFromCharCode = String.fromCharCode; var floor = Math.floor; var fromCodePoint = function () { var MAX_SIZE = 0x4000; var codeUnits = []; var highSurrogate; var lowSurrogate; var index = -1; var length = arguments.length; if (!length) { return ""; } var result = ""; while (++index < length) { var codePoint = Number(arguments[index]); if ( !isFinite(codePoint) || // `NaN`, `+Infinity`, or `-Infinity` codePoint < 0 || // not a valid Unicode code point codePoint > 0x10ffff || // not a valid Unicode code point floor(codePoint) != codePoint // not an integer ) { throw RangeError("Invalid code point: " + codePoint); } if (codePoint <= 0xffff) { // BMP code point codeUnits.push(codePoint); } else { // Astral code point; split in surrogate halves // http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae codePoint -= 0x10000; highSurrogate = (codePoint >> 10) + 0xd800; lowSurrogate = (codePoint % 0x400) + 0xdc00; codeUnits.push(highSurrogate, lowSurrogate); } if (index + 1 == length || codeUnits.length > MAX_SIZE) { result += stringFromCharCode.apply(null, codeUnits); codeUnits.length = 0; } } return result; }; if (defineProperty) { defineProperty(String, "fromCodePoint", { value: fromCodePoint, configurable: true, writable: true, }); } else { String.fromCodePoint = fromCodePoint; } })(); }