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EDIT :: punycode.js

'use strict'; /** Highest positive signed 32-bit float value */ const maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1 /** Bootstring parameters */ const base = 36; const tMin = 1; const tMax = 26; const skew = 38; const damp = 700; const initialBias = 72; const initialN = 128; // 0x80 const delimiter = '-'; // '\x2D' /** Regular expressions */ const regexPunycode = /^xn--/; const regexNonASCII = /[^\0-\x7E]/; // non-ASCII chars const regexSeparators = /[\x2E\u3002\uFF0E\uFF61]/g; // RFC 3490 separators /** Error messages */ const errors = { 'overflow': 'Overflow: input needs wider integers to process', 'not-basic': 'Illegal input >= 0x80 (not a basic code point)', 'invalid-input': 'Invalid input' }; /** Convenience shortcuts */ const baseMinusTMin = base - tMin; const floor = Math.floor; const stringFromCharCode = String.fromCharCode; /*--------------------------------------------------------------------------*/ /** * A generic error utility function. * @private * @param {String} type The error type. * @returns {Error} Throws a `RangeError` with the applicable error message. */ function error(type) { throw new RangeError(errors[type]); } /** * A generic `Array#map` utility function. * @private * @param {Array} array The array to iterate over. * @param {Function} callback The function that gets called for every array * item. * @returns {Array} A new array of values returned by the callback function. */ function map(array, fn) { const result = []; let length = array.length; while (length--) { result[length] = fn(array[length]); } return result; } /** * A simple `Array#map`-like wrapper to work with domain name strings or email * addresses. * @private * @param {String} domain The domain name or email address. * @param {Function} callback The function that gets called for every * character. * @returns {Array} A new string of characters returned by the callback * function. */ function mapDomain(string, fn) { const parts = string.split('@'); let result = ''; if (parts.length > 1) { // In email addresses, only the domain name should be punycoded. Leave // the local part (i.e. everything up to `@`) intact. result = parts[0] + '@'; string = parts[1]; } // Avoid `split(regex)` for IE8 compatibility. See #17. string = string.replace(regexSeparators, '\x2E'); const labels = string.split('.'); const encoded = map(labels, fn).join('.'); return result + encoded; } /** * Creates an array containing the numeric code points of each Unicode * character in the string. While JavaScript uses UCS-2 internally, * this function will convert a pair of surrogate halves (each of which * UCS-2 exposes as separate characters) into a single code point, * matching UTF-16. * @see `punycode.ucs2.encode` * @see <https://mathiasbynens.be/notes/javascript-encoding> * @memberOf punycode.ucs2 * @name decode * @param {String} string The Unicode input string (UCS-2). * @returns {Array} The new array of code points. */ function ucs2decode(string) { const output = []; let counter = 0; const length = string.length; while (counter < length) { const value = string.charCodeAt(counter++); if (value >= 0xD800 && value <= 0xDBFF && counter < length) { // It's a high surrogate, and there is a next character. const extra = string.charCodeAt(counter++); if ((extra & 0xFC00) == 0xDC00) { // Low surrogate. output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000); } else { // It's an unmatched surrogate; only append this code unit, in case the // next code unit is the high surrogate of a surrogate pair. output.push(value); counter--; } } else { output.push(value); } } return output; } /** * Creates a string based on an array of numeric code points. * @see `punycode.ucs2.decode` * @memberOf punycode.ucs2 * @name encode * @param {Array} codePoints The array of numeric code points. * @returns {String} The new Unicode string (UCS-2). */ const ucs2encode = array => String.fromCodePoint(...array); /** * Converts a basic code point into a digit/integer. * @see `digitToBasic()` * @private * @param {Number} codePoint The basic numeric code point value. * @returns {Number} The numeric value of a basic code point (for use in * representing integers) in the range `0` to `base - 1`, or `base` if * the code point does not represent a value. */ const basicToDigit = function(codePoint) { if (codePoint - 0x30 < 0x0A) { return codePoint - 0x16; } if (codePoint - 0x41 < 0x1A) { return codePoint - 0x41; } if (codePoint - 0x61 < 0x1A) { return codePoint - 0x61; } return base; }; /** * Converts a digit/integer into a basic code point. * @see `basicToDigit()` * @private * @param {Number} digit The numeric value of a basic code point. * @returns {Number} The basic code point whose value (when used for * representing integers) is `digit`, which needs to be in the range * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is * used; else, the lowercase form is used. The behavior is undefined * if `flag` is non-zero and `digit` has no uppercase form. */ const digitToBasic = function(digit, flag) { // 0..25 map to ASCII a..z or A..Z // 26..35 map to ASCII 0..9 return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5); }; /** * Bias adaptation function as per section 3.4 of RFC 3492. * https://tools.ietf.org/html/rfc3492#section-3.4 * @private */ const adapt = function(delta, numPoints, firstTime) { let k = 0; delta = firstTime ? floor(delta / damp) : delta >> 1; delta += floor(delta / numPoints); for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) { delta = floor(delta / baseMinusTMin); } return floor(k + (baseMinusTMin + 1) * delta / (delta + skew)); }; /** * Converts a Punycode string of ASCII-only symbols to a string of Unicode * symbols. * @memberOf punycode * @param {String} input The Punycode string of ASCII-only symbols. * @returns {String} The resulting string of Unicode symbols. */ const decode = function(input) { // Don't use UCS-2. const output = []; const inputLength = input.length; let i = 0; let n = initialN; let bias = initialBias; // Handle the basic code points: let `basic` be the number of input code // points before the last delimiter, or `0` if there is none, then copy // the first basic code points to the output. let basic = input.lastIndexOf(delimiter); if (basic < 0) { basic = 0; } for (let j = 0; j < basic; ++j) { // if it's not a basic code point if (input.charCodeAt(j) >= 0x80) { error('not-basic'); } output.push(input.charCodeAt(j)); } // Main decoding loop: start just after the last delimiter if any basic code // points were copied; start at the beginning otherwise. for (let index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) { // `index` is the index of the next character to be consumed. // Decode a generalized variable-length integer into `delta`, // which gets added to `i`. The overflow checking is easier // if we increase `i` as we go, then subtract off its starting // value at the end to obtain `delta`. let oldi = i; for (let w = 1, k = base; /* no condition */; k += base) { if (index >= inputLength) { error('invalid-input'); } const digit = basicToDigit(input.charCodeAt(index++)); if (digit >= base || digit > floor((maxInt - i) / w)) { error('overflow'); } i += digit * w; const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias); if (digit < t) { break; } const baseMinusT = base - t; if (w > floor(maxInt / baseMinusT)) { error('overflow'); } w *= baseMinusT; } const out = output.length + 1; bias = adapt(i - oldi, out, oldi == 0); // `i` was supposed to wrap around from `out` to `0`, // incrementing `n` each time, so we'll fix that now: if (floor(i / out) > maxInt - n) { error('overflow'); } n += floor(i / out); i %= out; // Insert `n` at position `i` of the output. output.splice(i++, 0, n); } return String.fromCodePoint(...output); }; /** * Converts a string of Unicode symbols (e.g. a domain name label) to a * Punycode string of ASCII-only symbols. * @memberOf punycode * @param {String} input The string of Unicode symbols. * @returns {String} The resulting Punycode string of ASCII-only symbols. */ const encode = function(input) { const output = []; // Convert the input in UCS-2 to an array of Unicode code points. input = ucs2decode(input); // Cache the length. let inputLength = input.length; // Initialize the state. let n = initialN; let delta = 0; let bias = initialBias; // Handle the basic code points. for (const currentValue of input) { if (currentValue < 0x80) { output.push(stringFromCharCode(currentValue)); } } let basicLength = output.length; let handledCPCount = basicLength; // `handledCPCount` is the number of code points that have been handled; // `basicLength` is the number of basic code points. // Finish the basic string with a delimiter unless it's empty. if (basicLength) { output.push(delimiter); } // Main encoding loop: while (handledCPCount < inputLength) { // All non-basic code points < n have been handled already. Find the next // larger one: let m = maxInt; for (const currentValue of input) { if (currentValue >= n && currentValue < m) { m = currentValue; } } // Increase `delta` enough to advance the decoder's <n,i> state to <m,0>, // but guard against overflow. const handledCPCountPlusOne = handledCPCount + 1; if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) { error('overflow'); } delta += (m - n) * handledCPCountPlusOne; n = m; for (const currentValue of input) { if (currentValue < n && ++delta > maxInt) { error('overflow'); } if (currentValue == n) { // Represent delta as a generalized variable-length integer. let q = delta; for (let k = base; /* no condition */; k += base) { const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias); if (q < t) { break; } const qMinusT = q - t; const baseMinusT = base - t; output.push( stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0)) ); q = floor(qMinusT / baseMinusT); } output.push(stringFromCharCode(digitToBasic(q, 0))); bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength); delta = 0; ++handledCPCount; } } ++delta; ++n; } return output.join(''); }; /** * Converts a Punycode string representing a domain name or an email address * to Unicode. Only the Punycoded parts of the input will be converted, i.e. * it doesn't matter if you call it on a string that has already been * converted to Unicode. * @memberOf punycode * @param {String} input The Punycoded domain name or email address to * convert to Unicode. * @returns {String} The Unicode representation of the given Punycode * string. */ const toUnicode = function(input) { return mapDomain(input, function(string) { return regexPunycode.test(string) ? decode(string.slice(4).toLowerCase()) : string; }); }; /** * Converts a Unicode string representing a domain name or an email address to * Punycode. Only the non-ASCII parts of the domain name will be converted, * i.e. it doesn't matter if you call it with a domain that's already in * ASCII. * @memberOf punycode * @param {String} input The domain name or email address to convert, as a * Unicode string. * @returns {String} The Punycode representation of the given domain name or * email address. */ const toASCII = function(input) { return mapDomain(input, function(string) { return regexNonASCII.test(string) ? 'xn--' + encode(string) : string; }); }; /*--------------------------------------------------------------------------*/ /** Define the public API */ const punycode = { /** * A string representing the current Punycode.js version number. * @memberOf punycode * @type String */ 'version': '2.1.0', /** * An object of methods to convert from JavaScript's internal character * representation (UCS-2) to Unicode code points, and back. * @see <https://mathiasbynens.be/notes/javascript-encoding> * @memberOf punycode * @type Object */ 'ucs2': { 'decode': ucs2decode, 'encode': ucs2encode }, 'decode': decode, 'encode': encode, 'toASCII': toASCII, 'toUnicode': toUnicode }; module.exports = punycode;

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