node/node_modules/socket.io-client/lib/json.js

   1
   2 /**
   3  * socket.io
   4  * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
   5  * MIT Licensed
   6  */
   7
   8 /**
   9  * Based on JSON2 (http://www.JSON.org/js.html).
  10  */
  11
  12 (function (exports, nativeJSON) {
  13   "use strict";
  14
  15   // use native JSON if it's available
  16   if (nativeJSON && nativeJSON.parse){
  17     return exports.JSON = {
  18       parse: nativeJSON.parse
  19     , stringify: nativeJSON.stringify
  20     }
  21   }
  22
  23   var JSON = exports.JSON = {};
  24
  25   function f(n) {
  26       // Format integers to have at least two digits.
  27       return n < 10 ? '0' + n : n;
  28   }
  29
  30   function date(d, key) {
  31     return isFinite(d.valueOf()) ?
  32         d.getUTCFullYear()     + '-' +
  33         f(d.getUTCMonth() + 1) + '-' +
  34         f(d.getUTCDate())      + 'T' +
  35         f(d.getUTCHours())     + ':' +
  36         f(d.getUTCMinutes())   + ':' +
  37         f(d.getUTCSeconds())   + 'Z' : null;
  38   };
  39
  40   var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
  41       escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
  42       gap,
  43       indent,
  44       meta = {    // table of character substitutions
  45           '\b': '\\b',
  46           '\t': '\\t',
  47           '\n': '\\n',
  48           '\f': '\\f',
  49           '\r': '\\r',
  50           '"' : '\\"',
  51           '\\': '\\\\'
  52       },
  53       rep;
  54
  55
  56   function quote(string) {
  57
  58 // If the string contains no control characters, no quote characters, and no
  59 // backslash characters, then we can safely slap some quotes around it.
  60 // Otherwise we must also replace the offending characters with safe escape
  61 // sequences.
  62
  63       escapable.lastIndex = 0;
  64       return escapable.test(string) ? '"' + string.replace(escapable, function (a) {
  65           var c = meta[a];
  66           return typeof c === 'string' ? c :
  67               '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
  68       }) + '"' : '"' + string + '"';
  69   }
  70
  71
  72   function str(key, holder) {
  73
  74 // Produce a string from holder[key].
  75
  76       var i,          // The loop counter.
  77           k,          // The member key.
  78           v,          // The member value.
  79           length,
  80           mind = gap,
  81           partial,
  82           value = holder[key];
  83
  84 // If the value has a toJSON method, call it to obtain a replacement value.
  85
  86       if (value instanceof Date) {
  87           value = date(key);
  88       }
  89
  90 // If we were called with a replacer function, then call the replacer to
  91 // obtain a replacement value.
  92
  93       if (typeof rep === 'function') {
  94           value = rep.call(holder, key, value);
  95       }
  96
  97 // What happens next depends on the value's type.
  98
  99       switch (typeof value) {
 100       case 'string':
 101           return quote(value);
 102
 103       case 'number':
 104
 105 // JSON numbers must be finite. Encode non-finite numbers as null.
 106
 107           return isFinite(value) ? String(value) : 'null';
 108
 109       case 'boolean':
 110       case 'null':
 111
 112 // If the value is a boolean or null, convert it to a string. Note:
 113 // typeof null does not produce 'null'. The case is included here in
 114 // the remote chance that this gets fixed someday.
 115
 116           return String(value);
 117
 118 // If the type is 'object', we might be dealing with an object or an array or
 119 // null.
 120
 121       case 'object':
 122
 123 // Due to a specification blunder in ECMAScript, typeof null is 'object',
 124 // so watch out for that case.
 125
 126           if (!value) {
 127               return 'null';
 128           }
 129
 130 // Make an array to hold the partial results of stringifying this object value.
 131
 132           gap += indent;
 133           partial = [];
 134
 135 // Is the value an array?
 136
 137           if (Object.prototype.toString.apply(value) === '[object Array]') {
 138
 139 // The value is an array. Stringify every element. Use null as a placeholder
 140 // for non-JSON values.
 141
 142               length = value.length;
 143               for (i = 0; i < length; i += 1) {
 144                   partial[i] = str(i, value) || 'null';
 145               }
 146
 147 // Join all of the elements together, separated with commas, and wrap them in
 148 // brackets.
 149
 150               v = partial.length === 0 ? '[]' : gap ?
 151                   '[\n' + gap + partial.join(',\n' + gap) + '\n' + mind + ']' :
 152                   '[' + partial.join(',') + ']';
 153               gap = mind;
 154               return v;
 155           }
 156
 157 // If the replacer is an array, use it to select the members to be stringified.
 158
 159           if (rep && typeof rep === 'object') {
 160               length = rep.length;
 161               for (i = 0; i < length; i += 1) {
 162                   if (typeof rep[i] === 'string') {
 163                       k = rep[i];
 164                       v = str(k, value);
 165                       if (v) {
 166                           partial.push(quote(k) + (gap ? ': ' : ':') + v);
 167                       }
 168                   }
 169               }
 170           } else {
 171
 172 // Otherwise, iterate through all of the keys in the object.
 173
 174               for (k in value) {
 175                   if (Object.prototype.hasOwnProperty.call(value, k)) {
 176                       v = str(k, value);
 177                       if (v) {
 178                           partial.push(quote(k) + (gap ? ': ' : ':') + v);
 179                       }
 180                   }
 181               }
 182           }
 183
 184 // Join all of the member texts together, separated with commas,
 185 // and wrap them in braces.
 186
 187           v = partial.length === 0 ? '{}' : gap ?
 188               '{\n' + gap + partial.join(',\n' + gap) + '\n' + mind + '}' :
 189               '{' + partial.join(',') + '}';
 190           gap = mind;
 191           return v;
 192       }
 193   }
 194
 195 // If the JSON object does not yet have a stringify method, give it one.
 196
 197   JSON.stringify = function (value, replacer, space) {
 198
 199 // The stringify method takes a value and an optional replacer, and an optional
 200 // space parameter, and returns a JSON text. The replacer can be a function
 201 // that can replace values, or an array of strings that will select the keys.
 202 // A default replacer method can be provided. Use of the space parameter can
 203 // produce text that is more easily readable.
 204
 205       var i;
 206       gap = '';
 207       indent = '';
 208
 209 // If the space parameter is a number, make an indent string containing that
 210 // many spaces.
 211
 212       if (typeof space === 'number') {
 213           for (i = 0; i < space; i += 1) {
 214               indent += ' ';
 215           }
 216
 217 // If the space parameter is a string, it will be used as the indent string.
 218
 219       } else if (typeof space === 'string') {
 220           indent = space;
 221       }
 222
 223 // If there is a replacer, it must be a function or an array.
 224 // Otherwise, throw an error.
 225
 226       rep = replacer;
 227       if (replacer && typeof replacer !== 'function' &&
 228               (typeof replacer !== 'object' ||
 229               typeof replacer.length !== 'number')) {
 230           throw new Error('JSON.stringify');
 231       }
 232
 233 // Make a fake root object containing our value under the key of ''.
 234 // Return the result of stringifying the value.
 235
 236       return str('', {'': value});
 237   };
 238
 239 // If the JSON object does not yet have a parse method, give it one.
 240
 241   JSON.parse = function (text, reviver) {
 242   // The parse method takes a text and an optional reviver function, and returns
 243   // a JavaScript value if the text is a valid JSON text.
 244
 245       var j;
 246
 247       function walk(holder, key) {
 248
 249   // The walk method is used to recursively walk the resulting structure so
 250   // that modifications can be made.
 251
 252           var k, v, value = holder[key];
 253           if (value && typeof value === 'object') {
 254               for (k in value) {
 255                   if (Object.prototype.hasOwnProperty.call(value, k)) {
 256                       v = walk(value, k);
 257                       if (v !== undefined) {
 258                           value[k] = v;
 259                       } else {
 260                           delete value[k];
 261                       }
 262                   }
 263               }
 264           }
 265           return reviver.call(holder, key, value);
 266       }
 267
 268
 269   // Parsing happens in four stages. In the first stage, we replace certain
 270   // Unicode characters with escape sequences. JavaScript handles many characters
 271   // incorrectly, either silently deleting them, or treating them as line endings.
 272
 273       text = String(text);
 274       cx.lastIndex = 0;
 275       if (cx.test(text)) {
 276           text = text.replace(cx, function (a) {
 277               return '\\u' +
 278                   ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
 279           });
 280       }
 281
 282   // In the second stage, we run the text against regular expressions that look
 283   // for non-JSON patterns. We are especially concerned with '()' and 'new'
 284   // because they can cause invocation, and '=' because it can cause mutation.
 285   // But just to be safe, we want to reject all unexpected forms.
 286
 287   // We split the second stage into 4 regexp operations in order to work around
 288   // crippling inefficiencies in IE's and Safari's regexp engines. First we
 289   // replace the JSON backslash pairs with '@' (a non-JSON character). Second, we
 290   // replace all simple value tokens with ']' characters. Third, we delete all
 291   // open brackets that follow a colon or comma or that begin the text. Finally,
 292   // we look to see that the remaining characters are only whitespace or ']' or
 293   // ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.
 294
 295       if (/^[\],:{}\s]*$/
 296               .test(text.replace(/\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g, '@')
 297                   .replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']')
 298                   .replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
 299
 300   // In the third stage we use the eval function to compile the text into a
 301   // JavaScript structure. The '{' operator is subject to a syntactic ambiguity
 302   // in JavaScript: it can begin a block or an object literal. We wrap the text
 303   // in parens to eliminate the ambiguity.
 304
 305           j = eval('(' + text + ')');
 306
 307   // In the optional fourth stage, we recursively walk the new structure, passing
 308   // each name/value pair to a reviver function for possible transformation.
 309
 310           return typeof reviver === 'function' ?
 311               walk({'': j}, '') : j;
 312       }
 313
 314   // If the text is not JSON parseable, then a SyntaxError is thrown.
 315
 316       throw new SyntaxError('JSON.parse');
 317   };
 318
 319 })(
 320     'undefined' != typeof io ? io : module.exports
 321   , typeof JSON !== 'undefined' ? JSON : undefined
 322 );