🚨 Unmaintained 🚨

JSON 3 is deprecated and no longer maintained. Please don't use it in new projects, and migrate existing projects to use the native `JSON.parse` and `JSON.stringify` instead.

Thanks to everyone who contributed patches or found it useful! ❤️

# JSON 3

JSON 3 was a JSON polyfill for older JavaScript platforms.

## About

JSON is a language-independent data interchange format based on a loose subset of the JavaScript grammar. Originally popularized by Douglas Crockford, the format was standardized in the fifth edition of the ECMAScript specification. The 5.1 edition, ratified in June 2011, incorporates several modifications to the grammar pertaining to the serialization of dates.

JSON 3 exposes two functions: `stringify()` for serializing a JavaScript value to JSON, and `parse()` for producing a JavaScript value from a JSON source string. The JSON 3 parser uses recursive descent instead of `eval` and regular expressions, which makes it slower on older platforms compared to JSON 2. The functions behave exactly as described in the ECMAScript spec, except for the date serialization discrepancy noted below.

The project is hosted on GitHub, along with the unit tests. It is part of the BestieJS family, a collection of best-in-class JavaScript libraries that promote cross-platform support, specification precedents, unit testing, and plenty of documentation.

## Date Serialization

JSON 3 deviates from the specification in one important way: it does not define `Date#toISOString()` or `Date#toJSON()`. This preserves CommonJS compatibility and avoids polluting native prototypes. Instead, date serialization is performed internally by the `stringify()` implementation: if a date object does not define a custom `toJSON()` method, it is serialized as a simplified ISO 8601 date-time string.

Several native `Date#toJSON()` implementations produce date time strings that do not conform to the grammar outlined in the spec. In these environments, JSON 3 will override the native `stringify()` implementation. There is an issue on file to make these tests less strict.

Portions of the date serialization code are adapted from the `date-shim` project.

# Usage

## Web Browsers

    <script src="//cdnjs.cloudflare.com/ajax/libs/json3/3.3.2/json3.min.js"></script>
    <script>
      JSON.stringify({"Hello": 123});
      // => '{"Hello":123}'
      JSON.parse("[[1, 2, 3], 1, 2, 3, 4]", function (key, value) {
        if (typeof value == "number") {
          value = value % 2 ? "Odd" : "Even";
        }
        return value;
      });
      // => [["Odd", "Even", "Odd"], "Odd", "Even", "Odd", "Even"]
    </script>

When used in a web browser, JSON 3 exposes an additional `JSON3` object containing the `noConflict()` and `runInContext()` functions, as well as aliases to the `stringify()` and `parse()` functions.

### <tt>noConflict</tt> and <tt>runInContext</tt>

- `JSON3.noConflict()` restores the original value of the global `JSON` object and returns a reference to the `JSON3` object.
- `JSON3.runInContext([context, exports])` initializes JSON 3 using the given `context` object (e.g., `window`, `global`, etc.), or the global object if omitted. If an `exports` object is specified, the `stringify()`, `parse()`, and `runInContext()` functions will be attached to it instead of a new object.

### Asynchronous Module Loaders

JSON 3 is defined as an anonymous module for compatibility with RequireJS, `curl.js`, and other asynchronous module loaders.

    <script src="//cdnjs.cloudflare.com/ajax/libs/require.js/2.1.10/require.js"></script>
    <script>
      require({
        "paths": {
          "json3": "./path/to/json3"
        }
      }, ["json3"], function (JSON) {
        JSON.parse("[1, 2, 3]");
        // => [1, 2, 3]
      });
    </script>

To avoid issues with third-party scripts, JSON 3 is exported to the global scope even when used with a module loader. If this behavior is undesired, `JSON3.noConflict()` can be used to restore the global `JSON` object to its original value.

Note: If you intend to use JSON3 alongside another module, please do not simply concatenate these modules together, as that would cause multiple `define` calls in one script, resulting in errors in AMD loaders. The `r.js` build optimizer can be used instead if you need a single compressed file for production.

## CommonJS Environments

    var JSON3 = require("./path/to/json3");
    JSON3.parse("[1, 2, 3]");
    // => [1, 2, 3]

## JavaScript Engines

    load("path/to/json3.js");
    JSON.stringify({"Hello": 123, "Good-bye": 456}, ["Hello"], "\t");
    // => '{\n\t"Hello": 123\n}'

# Compatibility

JSON 3 has been tested with the following web browsers, CommonJS environments, and JavaScript engines.

## Web Browsers

- Windows Internet Explorer, version 6.0 and higher
- Google Chrome, version 19.0 and higher
- Mozilla Firefox, version 2.0 and higher
- Apple Safari, version 3.0 and higher
- Opera 8.54 and higher
- SeaMonkey 1.0 and higher

## CommonJS Environments

- Node 0.6.21 and higher
- io.js 1.0.3 and higher
- RingoJS 0.9 and higher
- Narwhal 0.3.2

## JavaScript Engines

- Mozilla Rhino 1.7R3 and higher
- WebKit JSC
- Google V8

## Known Incompatibilities

- Attempting to serialize the `arguments` object may produce inconsistent results across environments due to specification version differences. As a workaround, please convert the `arguments` object to an array first: `JSON.stringify([].slice.call(arguments, 0))`.

## Required Native Methods

JSON 3 assumes that the following methods exist and function as described in the ECMAScript specification:

- The `Number`, `String`, `Array`, `Object`, `Date`, `SyntaxError`, and `TypeError` constructors.
- `String.fromCharCode`
- `Object#toString`
- `Object#hasOwnProperty`
- `Function#call`
- `Math.floor`
- `Number#toString`
- `Date#valueOf`
- `String.prototype`: `indexOf`, `charCodeAt`, `charAt`, `slice`, `replace`.
- `Array.prototype`: `push`, `pop`, `join`.