JSON.prune.js

// JSON.prune : a function to stringify any object without overflow
// two additional optional parameters :
//   - the maximal depth (default : 6)
//   - the maximal length of arrays (default : 50)
// You can also pass an "options" object.
// examples :
//   var json = JSON.prune(window)
//   var arr = Array.apply(0,Array(1000)); var json = JSON.prune(arr, 4, 20)
//   var json = JSON.prune(window.location, {inheritedProperties:true})
// Web site : http://dystroy.org/JSON.prune/
// JSON.prune on github : https://github.com/Canop/JSON.prune
// This was discussed here : http://stackoverflow.com/q/13861254/263525
// The code is based on Douglas Crockford's code : https://github.com/douglascrockford/JSON-js/blob/master/json2.js
// No effort was done to support old browsers. JSON.prune will fail on IE8.
(function () {
	'use strict';

	var DEFAULT_MAX_DEPTH = 6;
	var DEFAULT_ARRAY_MAX_LENGTH = 50;
	var DEFAULT_PRUNED_VALUE = '"-pruned-"';
	var seen; // Same variable used for all stringifications
	var iterator; // either forEachEnumerableOwnProperty, forEachEnumerableProperty or forEachProperty

	// iterates on enumerable own properties (default behavior)
	var forEachEnumerableOwnProperty = function(obj, callback) {
		for (var k in obj) {
			if (Object.prototype.hasOwnProperty.call(obj, k)) callback(k);
		}
	};
	// iterates on enumerable properties
	var forEachEnumerableProperty = function(obj, callback) {
		for (var k in obj) callback(k);
	};
	// iterates on properties, even non enumerable and inherited ones
	// This is dangerous
	var forEachProperty = function(obj, callback, excluded) {
		if (obj==null) return;
		excluded = excluded || {};
		Object.getOwnPropertyNames(obj).forEach(function(k){
			if (!excluded[k]) {
				callback(k);
				excluded[k] = true;
			}
		});
		forEachProperty(Object.getPrototypeOf(obj), callback, excluded);
	};

	Object.defineProperty(Date.prototype, "toPrunedJSON", {value:Date.prototype.toJSON});

	var	cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
		escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
		meta = {	// table of character substitutions
			'\b': '\\b',
			'\t': '\\t',
			'\n': '\\n',
			'\f': '\\f',
			'\r': '\\r',
			'"' : '\\"',
			'\\': '\\\\'
		};

	function quote(string) {
		escapable.lastIndex = 0;
		return escapable.test(string) ? '"' + string.replace(escapable, function (a) {
			var c = meta[a];
			return typeof c === 'string'
				? c
				: '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
		}) + '"' : '"' + string + '"';
	}


	var prune = function (value, depthDecr, arrayMaxLength) {
		var prunedString = DEFAULT_PRUNED_VALUE;
		var replacer;
		if (typeof depthDecr == "object") {
			var options = depthDecr;
			depthDecr = options.depthDecr;
			arrayMaxLength = options.arrayMaxLength;
			iterator = options.iterator || forEachEnumerableOwnProperty;
			if (options.allProperties) iterator = forEachProperty;
			else if (options.inheritedProperties) iterator = forEachEnumerableProperty
			if ("prunedString" in options) {
				prunedString = options.prunedString;
			}
			if (options.replacer) {
				replacer = options.replacer;
			}
		} else {
			iterator = forEachEnumerableOwnProperty;
		}
		seen = [];
		depthDecr = depthDecr || DEFAULT_MAX_DEPTH;
		arrayMaxLength = arrayMaxLength || DEFAULT_ARRAY_MAX_LENGTH;
		function str(key, holder, depthDecr) {
			var i, k, v, length, partial, value = holder[key];

			if (value && typeof value === 'object' && typeof value.toPrunedJSON === 'function') {
				value = value.toPrunedJSON(key);
			}
			if (value && typeof value.toJSON === 'function') {
				value = value.toJSON();
			}

			switch (typeof value) {
			case 'string':
				return quote(value);
			case 'number':
				return isFinite(value) ? String(value) : 'null';
			case 'boolean':
			case 'null':
				return String(value);
			case 'object':
				if (!value) {
					return 'null';
				}
				if (depthDecr<=0 || seen.indexOf(value)!==-1) {
					if (replacer) {
						var replacement = replacer(value, prunedString, true);
						return replacement===undefined ? undefined : ''+replacement;
					}
					return prunedString;
				}
				seen.push(value);
				partial = [];
				if (Object.prototype.toString.apply(value) === '[object Array]') {
					length = Math.min(value.length, arrayMaxLength);
					for (i = 0; i < length; i += 1) {
						partial[i] = str(i, value, depthDecr-1) || 'null';
					}
					v = '[' + partial.join(',') + ']';
					if (replacer && value.length>arrayMaxLength) return replacer(value, v, false);
					return v;
				}
				if (value instanceof RegExp) {
					return quote(value.toString());
				}
				iterator(value, function(k) {
					try {
						v = str(k, value, depthDecr-1);
						if (v) partial.push(quote(k) + ':' + v);
					} catch (e) {
						// this try/catch due to forbidden accessors on some objects
					}
				});
				return '{' + partial.join(',') + '}';
			case 'function':
			case 'undefined':
				return replacer ? replacer(value, undefined, false) : undefined;
			}
		}
		return str('', {'': value}, depthDecr);
	};

	prune.log = function() {
		console.log.apply(console, Array.prototype.map.call(arguments, function(v) {
			return JSON.parse(JSON.prune(v));
		}));
	};
	prune.forEachProperty = forEachProperty; // you might want to also assign it to Object.forEachProperty

	if (typeof module !== "undefined") module.exports = prune;
	else JSON.prune = prune;
}());