462 lines
16 KiB
JavaScript
462 lines
16 KiB
JavaScript
/*
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http://www.JSON.org/json2.js
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2008-03-24
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Public Domain.
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NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
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See http://www.JSON.org/js.html
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This file creates a global JSON object containing three methods: stringify,
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parse, and quote.
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JSON.stringify(value, replacer, space)
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value any JavaScript value, usually an object or array.
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replacer an optional parameter that determines how object
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values are stringified for objects without a toJSON
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method. It can be a function or an array.
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space an optional parameter that specifies the indentation
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of nested structures. If it is omitted, the text will
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be packed without extra whitespace. If it is a number,
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it will specify the number of spaces to indent at each
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level. If it is a string (such as '\t'), it contains the
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characters used to indent at each level.
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This method produces a JSON text from a JavaScript value.
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When an object value is found, if the object contains a toJSON
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method, its toJSON method will be called and the result will be
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stringified. A toJSON method does not serialize: it returns the
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value represented by the name/value pair that should be serialized,
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or undefined if nothing should be serialized. The toJSON method will
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be passed the key associated with the value, and this will be bound
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to the object holding the key.
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This is the toJSON method added to Dates:
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function toJSON(key) {
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return this.getUTCFullYear() + '-' +
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f(this.getUTCMonth() + 1) + '-' +
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f(this.getUTCDate()) + 'T' +
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f(this.getUTCHours()) + ':' +
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f(this.getUTCMinutes()) + ':' +
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f(this.getUTCSeconds()) + 'Z';
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}
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You can provide an optional replacer method. It will be passed the
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key and value of each member, with this bound to the containing
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object. The value that is returned from your method will be
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serialized. If your method returns undefined, then the member will
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be excluded from the serialization.
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If no replacer parameter is provided, then a default replacer
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will be used:
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function replacer(key, value) {
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return Object.hasOwnProperty.call(this, key) ?
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value : undefined;
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}
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The default replacer is passed the key and value for each item in
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the structure. It excludes inherited members.
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If the replacer parameter is an array, then it will be used to
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select the members to be serialized. It filters the results such
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that only members with keys listed in the replacer array are
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stringified.
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Values that do not have JSON representaions, such as undefined or
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functions, will not be serialized. Such values in objects will be
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dropped; in arrays they will be replaced with null. You can use
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a replacer function to replace those with JSON values.
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JSON.stringify(undefined) returns undefined.
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The optional space parameter produces a stringification of the value
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that is filled with line breaks and indentation to make it easier to
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read.
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If the space parameter is a non-empty string, then that string will
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be used for indentation. If the space parameter is a number, then
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then indentation will be that many spaces.
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Example:
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text = JSON.stringify(['e', {pluribus: 'unum'}]);
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// text is '["e",{"pluribus":"unum"}]'
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text = JSON.stringify(['e', {pluribus: 'unum'}], null, '\t');
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// text is '[\n\t"e",\n\t{\n\t\t"pluribus": "unum"\n\t}\n]'
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JSON.parse(text, reviver)
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This method parses a JSON text to produce an object or array.
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It can throw a SyntaxError exception.
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The optional reviver parameter is a function that can filter and
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transform the results. It receives each of the keys and values,
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and its return value is used instead of the original value.
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If it returns what it received, then the structure is not modified.
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If it returns undefined then the member is deleted.
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Example:
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// Parse the text. Values that look like ISO date strings will
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// be converted to Date objects.
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myData = JSON.parse(text, function (key, value) {
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var a;
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if (typeof value === 'string') {
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a =
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/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);
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if (a) {
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return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],
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+a[5], +a[6]));
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}
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}
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return value;
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});
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JSON.quote(text)
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This method wraps a string in quotes, escaping some characters
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as needed.
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This is a reference implementation. You are free to copy, modify, or
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redistribute.
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USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD THIRD PARTY
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CODE INTO YOUR PAGES.
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*/
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/*jslint regexp: true, forin: true, evil: true */
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/*global JSON */
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/*members "", "\b", "\t", "\n", "\f", "\r", "\"", JSON, "\\", apply,
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call, charCodeAt, floor, getUTCDate, getUTCFullYear, getUTCHours,
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getUTCMinutes, getUTCMonth, getUTCSeconds, hasOwnProperty, join, length,
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parse, propertyIsEnumerable, prototype, push, quote, replace, stringify,
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test, toJSON, toString
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*/
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if (!this.JSON) {
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// Create a JSON object only if one does not already exist. We create the
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// object in a closure to avoid global variables.
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JSON = function () {
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function f(n) { // Format integers to have at least two digits.
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return n < 10 ? '0' + n : n;
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}
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Date.prototype.toJSON = function () {
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// Eventually, this method will be based on the date.toISOString method.
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return this.getUTCFullYear() + '-' +
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f(this.getUTCMonth() + 1) + '-' +
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f(this.getUTCDate()) + 'T' +
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f(this.getUTCHours()) + ':' +
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f(this.getUTCMinutes()) + ':' +
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f(this.getUTCSeconds()) + 'Z';
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};
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var escapeable = /["\\\x00-\x1f\x7f-\x9f]/g,
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gap,
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indent,
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meta = { // table of character substitutions
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'\b': '\\b',
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'\t': '\\t',
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'\n': '\\n',
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'\f': '\\f',
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'\r': '\\r',
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'"' : '\\"',
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'\\': '\\\\'
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},
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rep;
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function quote(string) {
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// If the string contains no control characters, no quote characters, and no
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// backslash characters, then we can safely slap some quotes around it.
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// Otherwise we must also replace the offending characters with safe escape
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// sequences.
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return escapeable.test(string) ?
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'"' + string.replace(escapeable, function (a) {
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var c = meta[a];
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if (typeof c === 'string') {
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return c;
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}
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c = a.charCodeAt();
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return '\\u00' + Math.floor(c / 16).toString(16) +
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(c % 16).toString(16);
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}) + '"' :
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'"' + string + '"';
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}
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function str(key, holder) {
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// Produce a string from holder[key].
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var i, // The loop counter.
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k, // The member key.
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v, // The member value.
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length,
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mind = gap,
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partial,
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value = holder[key];
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// If the value has a toJSON method, call it to obtain a replacement value.
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if (value && typeof value === 'object' &&
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typeof value.toJSON === 'function') {
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value = value.toJSON(key);
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}
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// If we were called with a replacer function, then call the replacer to
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// obtain a replacement value.
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if (typeof rep === 'function') {
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value = rep.call(holder, key, value);
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}
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// What happens next depends on the value's type.
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switch (typeof value) {
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case 'string':
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return quote(value);
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case 'number':
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// JSON numbers must be finite. Encode non-finite numbers as null.
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return isFinite(value) ? String(value) : 'null';
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case 'boolean':
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case 'null':
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// If the value is a boolean or null, convert it to a string. Note:
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// typeof null does not produce 'null'. The case is included here in
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// the remote chance that this gets fixed someday.
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return String(value);
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// If the type is 'object', we might be dealing with an object or an array or
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// null.
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case 'object':
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// Due to a specification blunder in ECMAScript, typeof null is 'object',
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// so watch out for that case.
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if (!value) {
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return 'null';
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}
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// Make an array to hold the partial results of stringifying this object value.
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gap += indent;
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partial = [];
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// If the object has a dontEnum length property, we'll treat it as an array.
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if (typeof value.length === 'number' &&
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!(value.propertyIsEnumerable('length'))) {
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// The object is an array. Stringify every element. Use null as a placeholder
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// for non-JSON values.
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length = value.length;
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for (i = 0; i < length; i += 1) {
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partial[i] = str(i, value) || 'null';
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}
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// Join all of the elements together, separated with commas, and wrap them in
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// brackets.
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v = partial.length === 0 ? '[]' :
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gap ? '[\n' + gap + partial.join(',\n' + gap) +
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'\n' + mind + ']' :
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'[' + partial.join(',') + ']';
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gap = mind;
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return v;
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}
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// If the replacer is an array, use it to select the members to be stringified.
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if (typeof rep === 'object') {
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length = rep.length;
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for (i = 0; i < length; i += 1) {
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k = rep[i];
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if (typeof k === 'string') {
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v = str(k, value, rep);
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if (v) {
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partial.push(quote(k) + (gap ? ': ' : ':') + v);
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}
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}
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}
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} else {
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// Otherwise, iterate through all of the keys in the object.
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for (k in value) {
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v = str(k, value, rep);
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if (v) {
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partial.push(quote(k) + (gap ? ': ' : ':') + v);
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}
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}
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}
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// Join all of the member texts together, separated with commas,
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// and wrap them in braces.
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v = partial.length === 0 ? '{}' :
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gap ? '{\n' + gap + partial.join(',\n' + gap) +
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'\n' + mind + '}' :
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'{' + partial.join(',') + '}';
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gap = mind;
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return v;
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}
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}
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// Return the JSON object containing the stringify, parse, and quote methods.
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return {
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stringify: function (value, replacer, space) {
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// The stringify method takes a value and an optional replacer, and an optional
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// space parameter, and returns a JSON text. The replacer can be a function
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// that can replace values, or an array of strings that will select the keys.
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// A default replacer method can be provided. Use of the space parameter can
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// produce text that is more easily readable.
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var i;
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gap = '';
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indent = '';
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if (space) {
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// If the space parameter is a number, make an indent string containing that
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// many spaces.
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if (typeof space === 'number') {
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for (i = 0; i < space; i += 1) {
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indent += ' ';
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}
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// If the space parameter is a string, it will be used as the indent string.
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} else if (typeof space === 'string') {
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indent = space;
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}
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}
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// If there is no replacer parameter, use the default replacer.
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if (!replacer) {
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rep = function (key, value) {
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if (!Object.hasOwnProperty.call(this, key)) {
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return undefined;
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}
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return value;
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};
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// The replacer can be a function or an array. Otherwise, throw an error.
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} else if (typeof replacer === 'function' ||
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(typeof replacer === 'object' &&
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typeof replacer.length === 'number')) {
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rep = replacer;
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} else {
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throw new Error('JSON.stringify');
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}
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// Make a fake root object containing our value under the key of ''.
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// Return the result of stringifying the value.
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return str('', {'': value});
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},
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parse: function (text, reviver) {
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// The parse method takes a text and an optional reviver function, and returns
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// a JavaScript value if the text is a valid JSON text.
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var j;
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function walk(holder, key) {
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// The walk method is used to recursively walk the resulting structure so
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// that modifications can be made.
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var k, v, value = holder[key];
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if (value && typeof value === 'object') {
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for (k in value) {
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if (Object.hasOwnProperty.call(value, k)) {
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v = walk(value, k);
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if (v !== undefined) {
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value[k] = v;
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} else {
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delete value[k];
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}
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}
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}
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}
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return reviver.call(holder, key, value);
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}
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// Parsing happens in three stages. In the first stage, we run the text against
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// regular expressions that look for non-JSON patterns. We are especially
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// concerned with '()' and 'new' because they can cause invocation, and '='
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// because it can cause mutation. But just to be safe, we want to reject all
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// unexpected forms.
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// We split the first stage into 4 regexp operations in order to work around
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// crippling inefficiencies in IE's and Safari's regexp engines. First we
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// replace all backslash pairs with '@' (a non-JSON character). Second, we
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// replace all simple value tokens with ']' characters. Third, we delete all
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// open brackets that follow a colon or comma or that begin the text. Finally,
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// we look to see that the remaining characters are only whitespace or ']' or
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// ',' or ':' or '{' or '}'. If that is so, then the text is safe for eval.
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if (/^[\],:{}\s]*$/.test(text.replace(/\\["\\\/bfnrtu]/g, '@').
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replace(/"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g, ']').
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replace(/(?:^|:|,)(?:\s*\[)+/g, ''))) {
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// In the second stage we use the eval function to compile the text into a
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// JavaScript structure. The '{' operator is subject to a syntactic ambiguity
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// in JavaScript: it can begin a block or an object literal. We wrap the text
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// in parens to eliminate the ambiguity.
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j = eval('(' + text + ')');
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// In the optional third stage, we recursively walk the new structure, passing
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// each name/value pair to a reviver function for possible transformation.
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return typeof reviver === 'function' ?
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walk({'': j}, '') : j;
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}
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// If the text is not JSON parseable, then a SyntaxError is thrown.
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throw new SyntaxError('JSON.parse');
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},
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quote: quote
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};
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}();
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}
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