JSON 3 is **deprecated** and **no longer maintained**.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 was a JSON polyfill for older JavaScript platforms.
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.
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.
<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.
JSON3.noConflict()restores the original value of the globalJSONobject and returns a reference to theJSON3object.JSON3.runInContext([context, exports])initializes JSON 3 using the givencontextobject (e.g.,window,global, etc.), or the global object if omitted. If anexportsobject is specified, thestringify(),parse(), andrunInContext()functions will be attached to it instead of a new object.
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.
var JSON3 = require("./path/to/json3");
JSON3.parse("[1, 2, 3]");
// => [1, 2, 3]
load("path/to/json3.js");
JSON.stringify({"Hello": 123, "Good-bye": 456}, ["Hello"], "\t");
// => '{\n\t"Hello": 123\n}'
JSON 3 has been tested with the following web browsers, CommonJS environments, and JavaScript engines.
- 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
- Attempting to serialize the
argumentsobject may produce inconsistent results across environments due to specification version differences. As a workaround, please convert theargumentsobject to an array first:JSON.stringify([].slice.call(arguments, 0)).
JSON 3 assumes that the following methods exist and function as described in the ECMAScript specification:
- The
Number,String,Array,Object,Date,SyntaxError, andTypeErrorconstructors. String.fromCharCodeObject#toStringObject#hasOwnPropertyFunction#callMath.floorNumber#toStringDate#valueOfString.prototype:indexOf,charCodeAt,charAt,slice,replace.Array.prototype:push,pop,join.