JSON Encoder/Decoder For JavaScript

JSON(JavaScript Object Notation) is a lightweight computer data interchange format. It is a text-based, semi-readable format for representing simple data structures and associative arrays. The main advantage of using JSON is that it can be parsed into an object using very little code - and for this reason, many people(including me) prefer using it as the ajax response format.

JSON Decoder/Parser

As I said earlier, parsing JSON is very easy. All you have to do is...

var json_data_object = eval("(" + json_string + ")");

If you have moral objections with using eval, there are other JSON parsers that don't use eval. Use one of those.

JSON Encoder

Unlike decoding JSON, encoding JSON in JavaScript takes a bit of work. Usually you don't have to do that in the client side - generating JSON strings are the function of server side script. And server side language have functions for it. For example, PHP has json_encode.

But there are occasions when you want to encode a data structure into a string in JavaScript. A good example for this is saving data structures to a cookie. Cookies can only store strings. If you want to store a data structure in it, you have to use some encoding scheme. And since we are working in javascript, JSON is the obvious choice. I recently had to do this - so I wrote a function to encode a data structure into a JSON string. Yes, I know there are a lot of scripts that does this. But I like re-inventing the wheel - it is one of my favorite pass times.

Then again, I was not re-inventing a JSON encoder - I was just translating a JSON parser I wrote in PHP to javascript.

 * Converts the given data structure to a JSON string.
 * Argument: arr - The data structure that must be converted to JSON
 * Example: var json_string = array2json(['e', {pluribus: 'unum'}]);
 * 			var json = array2json({"success":"Sweet","failure":false,"empty_array":[],"numbers":[1,2,3],"info":{"name":"Binny","site":"http:\/\/www.openjs.com\/"}});
 * http://www.openjs.com/scripts/data/json_encode.php
function array2json(arr) {
    var parts = [];
    var is_list = (Object.prototype.toString.apply(arr) === '[object Array]');

    for(var key in arr) {
    	var value = arr[key];
        if(typeof value == "object") { //Custom handling for arrays
            if(is_list) parts.push(array2json(value)); /* :RECURSION: */
            else parts.push('"' + key + '":' + array2json(value)); /* :RECURSION: */
            //else parts[key] = array2json(value); /* :RECURSION: */
        } else {
            var str = "";
            if(!is_list) str = '"' + key + '":';

            //Custom handling for multiple data types
            if(typeof value == "number") str += value; //Numbers
            else if(value === false) str += 'false'; //The booleans
            else if(value === true) str += 'true';
            else str += '"' + value + '"'; //All other things
            // :TODO: Is there any more datatype we should be in the lookout for? (Functions?)

    var json = parts.join(",");
    if(is_list) return '[' + json + ']';//Return numerical JSON
    return '{' + json + '}';//Return associative JSON

Usage Example

var json_string = array2json(['e', {pluribus: 'unum'}]);//Returns '["e", {"pluribus": "unum"}]' 

var data = {
var json = array2json(data); // Returns {"success":"Sweet","failure":false,"empty_array":[],"numbers":[1,2,3],"info":{"name":"Binny","site":"http:\/\/www.openjs.com\/"}}


BSD License

blog comments powered by Disqus