/* Copyright (c) 2010, Yahoo! Inc. All rights reserved. Code licensed under the BSD License: http://developer.yahoo.com/yui/license.html version: 3.4.0 build: nightly */ YUI.add('json-stringify', function(Y) { /** * Provides Y.JSON.stringify method for converting objects to JSON strings. * * @module json * @submodule json-stringify * @for JSON * @static */ var _JSON = (Y.config.win || {}).JSON, Lang = Y.Lang, isFunction= Lang.isFunction, isObject = Lang.isObject, isArray = Lang.isArray, _toStr = Object.prototype.toString, Native = (_toStr.call(_JSON) === '[object JSON]' && _JSON), useNative = !!Native, UNDEFINED = 'undefined', OBJECT = 'object', NULL = 'null', STRING = 'string', NUMBER = 'number', BOOLEAN = 'boolean', DATE = 'date', _allowable= { 'undefined' : UNDEFINED, 'string' : STRING, '[object String]' : STRING, 'number' : NUMBER, '[object Number]' : NUMBER, 'boolean' : BOOLEAN, '[object Boolean]' : BOOLEAN, '[object Date]' : DATE, '[object RegExp]' : OBJECT }, EMPTY = '', OPEN_O = '{', CLOSE_O = '}', OPEN_A = '[', CLOSE_A = ']', COMMA = ',', COMMA_CR = ",\n", CR = "\n", COLON = ':', COLON_SP = ': ', QUOTE = '"', // Regex used to capture characters that need escaping before enclosing // their containing string in quotes. _SPECIAL = /[\x00-\x07\x0b\x0e-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g, // Character substitution map for common escapes and special characters. _COMMON = [ [/\\/g, '\\\\'], [/\"/g, '\\"'], [/\x08/g, '\\b'], [/\x09/g, '\\t'], [/\x0a/g, '\\n'], [/\x0c/g, '\\f'], [/\x0d/g, '\\r'] ], _COMMON_LENGTH = _COMMON.length, // In-process optimization for special character escapes that haven't yet // been promoted to _COMMON _CHAR = {}, // Per-char counter to determine if it's worth fast tracking a special // character escape sequence. _CHAR_COUNT, _CACHE_THRESHOLD; // Utility function used to determine how to serialize a variable. function _type(o) { var t = typeof o; return _allowable[t] || // number, string, boolean, undefined _allowable[_toStr.call(o)] || // Number, String, Boolean, Date (t === OBJECT ? (o ? OBJECT : NULL) : // object, array, null, misc natives UNDEFINED); // function, unknown } // Escapes a special character to a safe Unicode representation function _char(c) { if (!_CHAR[c]) { _CHAR[c] = '\\u'+('0000'+(+(c.charCodeAt(0))).toString(16)).slice(-4); _CHAR_COUNT[c] = 0; } // === to avoid this conditional for the remainder of the current operation if (++_CHAR_COUNT[c] === _CACHE_THRESHOLD) { _COMMON.push([new RegExp(c, 'g'), _CHAR[c]]); _COMMON_LENGTH = _COMMON.length; } return _CHAR[c]; } // Enclose escaped strings in quotes function _string(s) { var i, chr; // Preprocess the string against common characters to avoid function // overhead associated with replacement via function. for (i = 0; i < _COMMON_LENGTH; i++) { chr = _COMMON[i]; s = s.replace(chr[0], chr[1]); } // original function replace for the not-as-common set of chars return QUOTE + s.replace(_SPECIAL, _char) + QUOTE; } // Adds the provided space to the beginning of every line in the input string function _indent(s,space) { return s.replace(/^/gm, space); } // JavaScript implementation of stringify (see API declaration of stringify) function _stringify(o,w,space) { if (o === undefined) { return undefined; } var replacer = isFunction(w) ? w : null, format = _toStr.call(space).match(/String|Number/) || [], _date = Y.JSON.dateToString, stack = [], tmp,i,len; _CHAR_COUNT = {}; _CACHE_THRESHOLD = Y.JSON.charCacheThreshold; if (replacer || !isArray(w)) { w = undefined; } // Ensure whitelist keys are unique (bug 2110391) if (w) { tmp = {}; for (i = 0, len = w.length; i < len; ++i) { tmp[w[i]] = true; } w = tmp; } // Per the spec, strings are truncated to 10 characters and numbers // are converted to that number of spaces (max 10) space = format[0] === 'Number' ? new Array(Math.min(Math.max(0,space),10)+1).join(" ") : (space || EMPTY).slice(0,10); function _serialize(h,key) { var value = h[key], t = _type(value), a = [], colon = space ? COLON_SP : COLON, arr, i, keys, k, v; // Per the ECMA 5 spec, toJSON is applied before the replacer is // called. Also per the spec, Date.prototype.toJSON has been added, so // Date instances should be serialized prior to exposure to the // replacer. I disagree with this decision, but the spec is the spec. if (isObject(value) && isFunction(value.toJSON)) { value = value.toJSON(key); } else if (t === DATE) { value = _date(value); } if (isFunction(replacer)) { value = replacer.call(h,key,value); } if (value !== h[key]) { t = _type(value); } switch (t) { case DATE : // intentional fallthrough. Pre-replacer Dates are // serialized in the toJSON stage. Dates here would // have been produced by the replacer. case OBJECT : break; case STRING : return _string(value); case NUMBER : return isFinite(value) ? value+EMPTY : NULL; case BOOLEAN : return value+EMPTY; case NULL : return NULL; default : return undefined; } // Check for cyclical references in nested objects for (i = stack.length - 1; i >= 0; --i) { if (stack[i] === value) { throw new Error("JSON.stringify. Cyclical reference"); } } arr = isArray(value); // Add the object to the processing stack stack.push(value); if (arr) { // Array for (i = value.length - 1; i >= 0; --i) { a[i] = _serialize(value, i) || NULL; } } else { // Object // If whitelist provided, take only those keys keys = w || value; i = 0; for (k in keys) { if (keys.hasOwnProperty(k)) { v = _serialize(value, k); if (v) { a[i++] = _string(k) + colon + v; } } } } // remove the array from the stack stack.pop(); if (space && a.length) { return arr ? OPEN_A + CR + _indent(a.join(COMMA_CR), space) + CR + CLOSE_A : OPEN_O + CR + _indent(a.join(COMMA_CR), space) + CR + CLOSE_O; } else { return arr ? OPEN_A + a.join(COMMA) + CLOSE_A : OPEN_O + a.join(COMMA) + CLOSE_O; } } // process the input return _serialize({'':o},''); } // Double check basic native functionality. This is primarily to catch broken // early JSON API implementations in Firefox 3.1 beta1 and beta2. if ( Native ) { try { useNative = ( '0' === Native.stringify(0) ); } catch ( e ) { useNative = false; } } Y.mix(Y.namespace('JSON'),{ /** * Leverage native JSON stringify if the browser has a native * implementation. In general, this is a good idea. See the Known Issues * section in the JSON user guide for caveats. The default value is true * for browsers with native JSON support. * * @property useNativeStringify * @type Boolean * @default true * @static */ useNativeStringify : useNative, /** * Serializes a Date instance as a UTC date string. Used internally by * stringify. Override this method if you need Dates serialized in a * different format. * * @method dateToString * @param d {Date} The Date to serialize * @return {String} stringified Date in UTC format YYYY-MM-DDTHH:mm:SSZ * @deprecated Use a replacer function * @static */ dateToString : function (d) { function _zeroPad(v) { return v < 10 ? '0' + v : v; } return d.getUTCFullYear() + '-' + _zeroPad(d.getUTCMonth() + 1) + '-' + _zeroPad(d.getUTCDate()) + 'T' + _zeroPad(d.getUTCHours()) + COLON + _zeroPad(d.getUTCMinutes()) + COLON + _zeroPad(d.getUTCSeconds()) + 'Z'; }, /** *

Converts an arbitrary value to a JSON string representation.

* *

Objects with cyclical references will trigger an exception.

* *

If a whitelist is provided, only matching object keys will be * included. Alternately, a replacer function may be passed as the * second parameter. This function is executed on every value in the * input, and its return value will be used in place of the original value. * This is useful to serialize specialized objects or class instances.

* *

If a positive integer or non-empty string is passed as the third * parameter, the output will be formatted with carriage returns and * indentation for readability. If a String is passed (such as "\t") it * will be used once for each indentation level. If a number is passed, * that number of spaces will be used.

* * @method stringify * @param o {MIXED} any arbitrary value to convert to JSON string * @param w {Array|Function} (optional) whitelist of acceptable object * keys to include, or a replacer function to modify the * raw value before serialization * @param ind {Number|String} (optional) indentation character or depth of * spaces to format the output. * @return {string} JSON string representation of the input * @static */ stringify : function (o,w,ind) { return Native && Y.JSON.useNativeStringify ? Native.stringify(o,w,ind) : _stringify(o,w,ind); }, /** *

Number of occurrences of a special character within a single call to * stringify that should trigger promotion of that character to a dedicated * preprocess step for future calls. This is only used in environments * that don't support native JSON, or when useNativeStringify is set to * false.

* *

So, if set to 50 and an object is passed to stringify that includes * strings containing the special character \x07 more than 50 times, * subsequent calls to stringify will process object strings through a * faster serialization path for \x07 before using the generic, slower, * replacement process for all special characters.

* *

To prime the preprocessor cache, set this value to 1, then call * Y.JSON.stringify("(all special characters to * cache)");, then return this setting to a more conservative * value.

* *

Special characters \ " \b \t \n \f \r are already cached.

* * @property charCacheThreshold * @static * @default 100 * @type {Number} */ charCacheThreshold: 100 }); }, '3.4.0' ,{requires:['yui-base']});