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view js-lib/json2.js @ 94:0f19af92260e laserkard
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author | Robert McIntyre <rlm@mit.edu> |
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date | Mon, 26 Jul 2010 20:33:17 -0400 |
parents | 08f93d043ed2 |
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2 /*3 http://www.JSON.org/json2.js4 2010-03-206 Public Domain.8 NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.10 See http://www.JSON.org/js.html13 This code should be minified before deployment.14 See http://javascript.crockford.com/jsmin.html16 USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO17 NOT CONTROL.20 This file creates a global JSON object containing two methods: stringify21 and parse.23 JSON.stringify(value, replacer, space)24 value any JavaScript value, usually an object or array.26 replacer an optional parameter that determines how object27 values are stringified for objects. It can be a28 function or an array of strings.30 space an optional parameter that specifies the indentation31 of nested structures. If it is omitted, the text will32 be packed without extra whitespace. If it is a number,33 it will specify the number of spaces to indent at each34 level. If it is a string (such as '\t' or ' '),35 it contains the characters used to indent at each level.37 This method produces a JSON text from a JavaScript value.39 When an object value is found, if the object contains a toJSON40 method, its toJSON method will be called and the result will be41 stringified. A toJSON method does not serialize: it returns the42 value represented by the name/value pair that should be serialized,43 or undefined if nothing should be serialized. The toJSON method44 will be passed the key associated with the value, and this will be45 bound to the value47 For example, this would serialize Dates as ISO strings.49 Date.prototype.toJSON = function (key) {50 function f(n) {51 // Format integers to have at least two digits.52 return n < 10 ? '0' + n : n;53 }55 return this.getUTCFullYear() + '-' +56 f(this.getUTCMonth() + 1) + '-' +57 f(this.getUTCDate()) + 'T' +58 f(this.getUTCHours()) + ':' +59 f(this.getUTCMinutes()) + ':' +60 f(this.getUTCSeconds()) + 'Z';61 };63 You can provide an optional replacer method. It will be passed the64 key and value of each member, with this bound to the containing65 object. The value that is returned from your method will be66 serialized. If your method returns undefined, then the member will67 be excluded from the serialization.69 If the replacer parameter is an array of strings, then it will be70 used to select the members to be serialized. It filters the results71 such that only members with keys listed in the replacer array are72 stringified.74 Values that do not have JSON representations, such as undefined or75 functions, will not be serialized. Such values in objects will be76 dropped; in arrays they will be replaced with null. You can use77 a replacer function to replace those with JSON values.78 JSON.stringify(undefined) returns undefined.80 The optional space parameter produces a stringification of the81 value that is filled with line breaks and indentation to make it82 easier to read.84 If the space parameter is a non-empty string, then that string will85 be used for indentation. If the space parameter is a number, then86 the indentation will be that many spaces.88 Example:90 text = JSON.stringify(['e', {pluribus: 'unum'}]);91 // text is '["e",{"pluribus":"unum"}]'94 text = JSON.stringify(['e', {pluribus: 'unum'}], null, '\t');95 // text is '[\n\t"e",\n\t{\n\t\t"pluribus": "unum"\n\t}\n]'97 text = JSON.stringify([new Date()], function (key, value) {98 return this[key] instanceof Date ?99 'Date(' + this[key] + ')' : value;100 });101 // text is '["Date(---current time---)"]'104 JSON.parse(text, reviver)105 This method parses a JSON text to produce an object or array.106 It can throw a SyntaxError exception.108 The optional reviver parameter is a function that can filter and109 transform the results. It receives each of the keys and values,110 and its return value is used instead of the original value.111 If it returns what it received, then the structure is not modified.112 If it returns undefined then the member is deleted.114 Example:116 // Parse the text. Values that look like ISO date strings will117 // be converted to Date objects.119 myData = JSON.parse(text, function (key, value) {120 var a;121 if (typeof value === 'string') {122 a =123 /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);124 if (a) {125 return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],126 +a[5], +a[6]));127 }128 }129 return value;130 });132 myData = JSON.parse('["Date(09/09/2001)"]', function (key, value) {133 var d;134 if (typeof value === 'string' &&135 value.slice(0, 5) === 'Date(' &&136 value.slice(-1) === ')') {137 d = new Date(value.slice(5, -1));138 if (d) {139 return d;140 }141 }142 return value;143 });146 This is a reference implementation. You are free to copy, modify, or147 redistribute.148 */150 /*jslint evil: true, strict: false */152 /*members "", "\b", "\t", "\n", "\f", "\r", "\"", JSON, "\\", apply,153 call, charCodeAt, getUTCDate, getUTCFullYear, getUTCHours,154 getUTCMinutes, getUTCMonth, getUTCSeconds, hasOwnProperty, join,155 lastIndex, length, parse, prototype, push, replace, slice, stringify,156 test, toJSON, toString, valueOf157 */160 // Create a JSON object only if one does not already exist. We create the161 // methods in a closure to avoid creating global variables.163 if (!this.JSON) {164 this.JSON = {};165 }167 (function () {169 function f(n) {170 // Format integers to have at least two digits.171 return n < 10 ? '0' + n : n;172 }174 if (typeof Date.prototype.toJSON !== 'function') {176 Date.prototype.toJSON = function (key) {178 return isFinite(this.valueOf()) ?179 this.getUTCFullYear() + '-' +180 f(this.getUTCMonth() + 1) + '-' +181 f(this.getUTCDate()) + 'T' +182 f(this.getUTCHours()) + ':' +183 f(this.getUTCMinutes()) + ':' +184 f(this.getUTCSeconds()) + 'Z' : null;185 };187 String.prototype.toJSON =188 Number.prototype.toJSON =189 Boolean.prototype.toJSON = function (key) {190 return this.valueOf();191 };192 }194 var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,195 escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,196 gap,197 indent,198 meta = { // table of character substitutions199 '\b': '\\b',200 '\t': '\\t',201 '\n': '\\n',202 '\f': '\\f',203 '\r': '\\r',204 '"' : '\\"',205 '\\': '\\\\'206 },207 rep;210 function quote(string) {212 // If the string contains no control characters, no quote characters, and no213 // backslash characters, then we can safely slap some quotes around it.214 // Otherwise we must also replace the offending characters with safe escape215 // sequences.217 escapable.lastIndex = 0;218 return escapable.test(string) ?219 '"' + string.replace(escapable, function (a) {220 var c = meta[a];221 return typeof c === 'string' ? c :222 '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);223 }) + '"' :224 '"' + string + '"';225 }228 function str(key, holder) {230 // Produce a string from holder[key].232 var i, // The loop counter.233 k, // The member key.234 v, // The member value.235 length,236 mind = gap,237 partial,238 value = holder[key];240 // If the value has a toJSON method, call it to obtain a replacement value.242 if (value && typeof value === 'object' &&243 typeof value.toJSON === 'function') {244 value = value.toJSON(key);245 }247 // If we were called with a replacer function, then call the replacer to248 // obtain a replacement value.250 if (typeof rep === 'function') {251 value = rep.call(holder, key, value);252 }254 // What happens next depends on the value's type.256 switch (typeof value) {257 case 'string':258 return quote(value);260 case 'number':262 // JSON numbers must be finite. Encode non-finite numbers as null.264 return isFinite(value) ? String(value) : 'null';266 case 'boolean':267 case 'null':269 // If the value is a boolean or null, convert it to a string. Note:270 // typeof null does not produce 'null'. The case is included here in271 // the remote chance that this gets fixed someday.273 return String(value);275 // If the type is 'object', we might be dealing with an object or an array or276 // null.278 case 'object':280 // Due to a specification blunder in ECMAScript, typeof null is 'object',281 // so watch out for that case.283 if (!value) {284 return 'null';285 }287 // Make an array to hold the partial results of stringifying this object value.289 gap += indent;290 partial = [];292 // Is the value an array?294 if (Object.prototype.toString.apply(value) === '[object Array]') {296 // The value is an array. Stringify every element. Use null as a placeholder297 // for non-JSON values.299 length = value.length;300 for (i = 0; i < length; i += 1) {301 partial[i] = str(i, value) || 'null';302 }304 // Join all of the elements together, separated with commas, and wrap them in305 // brackets.307 v = partial.length === 0 ? '[]' :308 gap ? '[\n' + gap +309 partial.join(',\n' + gap) + '\n' +310 mind + ']' :311 '[' + partial.join(',') + ']';312 gap = mind;313 return v;314 }316 // If the replacer is an array, use it to select the members to be stringified.318 if (rep && typeof rep === 'object') {319 length = rep.length;320 for (i = 0; i < length; i += 1) {321 k = rep[i];322 if (typeof k === 'string') {323 v = str(k, value);324 if (v) {325 partial.push(quote(k) + (gap ? ': ' : ':') + v);326 }327 }328 }329 } else {331 // Otherwise, iterate through all of the keys in the object.333 for (k in value) {334 if (Object.hasOwnProperty.call(value, k)) {335 v = str(k, value);336 if (v) {337 partial.push(quote(k) + (gap ? ': ' : ':') + v);338 }339 }340 }341 }343 // Join all of the member texts together, separated with commas,344 // and wrap them in braces.346 v = partial.length === 0 ? '{}' :347 gap ? '{\n' + gap + partial.join(',\n' + gap) + '\n' +348 mind + '}' : '{' + partial.join(',') + '}';349 gap = mind;350 return v;351 }352 }354 // If the JSON object does not yet have a stringify method, give it one.356 if (typeof JSON.stringify !== 'function') {357 JSON.stringify = function (value, replacer, space) {359 // The stringify method takes a value and an optional replacer, and an optional360 // space parameter, and returns a JSON text. The replacer can be a function361 // that can replace values, or an array of strings that will select the keys.362 // A default replacer method can be provided. Use of the space parameter can363 // produce text that is more easily readable.365 var i;366 gap = '';367 indent = '';369 // If the space parameter is a number, make an indent string containing that370 // many spaces.372 if (typeof space === 'number') {373 for (i = 0; i < space; i += 1) {374 indent += ' ';375 }377 // If the space parameter is a string, it will be used as the indent string.379 } else if (typeof space === 'string') {380 indent = space;381 }383 // If there is a replacer, it must be a function or an array.384 // Otherwise, throw an error.386 rep = replacer;387 if (replacer && typeof replacer !== 'function' &&388 (typeof replacer !== 'object' ||389 typeof replacer.length !== 'number')) {390 throw new Error('JSON.stringify');391 }393 // Make a fake root object containing our value under the key of ''.394 // Return the result of stringifying the value.396 return str('', {'': value});397 };398 }401 // If the JSON object does not yet have a parse method, give it one.403 if (typeof JSON.parse !== 'function') {404 JSON.parse = function (text, reviver) {406 // The parse method takes a text and an optional reviver function, and returns407 // a JavaScript value if the text is a valid JSON text.409 var j;411 function walk(holder, key) {413 // The walk method is used to recursively walk the resulting structure so414 // that modifications can be made.416 var k, v, value = holder[key];417 if (value && typeof value === 'object') {418 for (k in value) {419 if (Object.hasOwnProperty.call(value, k)) {420 v = walk(value, k);421 if (v !== undefined) {422 value[k] = v;423 } else {424 delete value[k];425 }426 }427 }428 }429 return reviver.call(holder, key, value);430 }433 // Parsing happens in four stages. In the first stage, we replace certain434 // Unicode characters with escape sequences. JavaScript handles many characters435 // incorrectly, either silently deleting them, or treating them as line endings.437 text = String(text);438 cx.lastIndex = 0;439 if (cx.test(text)) {440 text = text.replace(cx, function (a) {441 return '\\u' +442 ('0000' + a.charCodeAt(0).toString(16)).slice(-4);443 });444 }446 // In the second stage, we run the text against regular expressions that look447 // for non-JSON patterns. We are especially concerned with '()' and 'new'448 // because they can cause invocation, and '=' because it can cause mutation.449 // But just to be safe, we want to reject all unexpected forms.451 // We split the second stage into 4 regexp operations in order to work around452 // crippling inefficiencies in IE's and Safari's regexp engines. First we453 // replace the JSON backslash pairs with '@' (a non-JSON character). Second, we454 // replace all simple value tokens with ']' characters. Third, we delete all455 // open brackets that follow a colon or comma or that begin the text. Finally,456 // we look to see that the remaining characters are only whitespace or ']' or457 // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.459 if (/^[\],:{}\s]*$/.460 test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@').461 replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').462 replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {464 // In the third stage we use the eval function to compile the text into a465 // JavaScript structure. The '{' operator is subject to a syntactic ambiguity466 // in JavaScript: it can begin a block or an object literal. We wrap the text467 // in parens to eliminate the ambiguity.469 j = eval('(' + text + ')');471 // In the optional fourth stage, we recursively walk the new structure, passing472 // each name/value pair to a reviver function for possible transformation.474 return typeof reviver === 'function' ?475 walk({'': j}, '') : j;476 }478 // If the text is not JSON parseable, then a SyntaxError is thrown.480 throw new SyntaxError('JSON.parse');481 };482 }483 }());