knockout.mapping.js

(function (factory) {
	// Module systems magic dance.

	if (typeof require === "function" && typeof exports === "object" && typeof module === "object") {
		// CommonJS or Node: hard-coded dependency on "knockout"
		factory(require("knockout"), exports);
	} else if (typeof define === "function" && define["amd"]) {
		// AMD anonymous module with hard-coded dependency on "knockout"
		define(["knockout", "exports"], factory);
	} else {
		// <script> tag: use the global `ko` object, attaching a `mapping` property
		factory(ko, ko.mapping = {});
	}
}(function (ko, exports) {
	var DEBUG=true;
	var mappingProperty = "__ko_mapping__";
	var realKoDependentObservable = ko.dependentObservable;
	var mappingNesting = 0;
	var dependentObservables;
	var visitedObjects;
	var recognizedRootProperties = ["create", "update", "key", "arrayChanged"];
	var emptyReturn = {};

	var _defaultOptions = {
		include: ["_destroy"],
		ignore: [],
		copy: [],
		observe: []
	};
	var defaultOptions = _defaultOptions;
	
	function unionArrays() {
		var args = arguments,
		l = args.length,
		obj = {},
		res = [],
		i, j, k;
		
		while (l--) {
			k = args[l];
			i = k.length;
			
			while (i--) {
				j = k[i];
				if (!obj[j]) {
					obj[j] = 1;
					res.push(j);
				}
			}	
		}
		
		return res;
	}

	function extendObject(destination, source) {
		var destType;

		for (var key in source) {
			if (source.hasOwnProperty(key) && source[key]) {
				destType = exports.getType(destination[key]);
				if (key && destination[key] && destType !== "array" && destType !== "string") {
					extendObject(destination[key], source[key]);
				} else {
					var bothArrays = exports.getType(destination[key]) === "array" && exports.getType(source[key]) === "array";
					if (bothArrays) {
						destination[key] = unionArrays(destination[key], source[key]);
					} else {
						destination[key] = source[key];
					}
				}
			}
		}
	}

	function merge(obj1, obj2) {
		var merged = {};
		extendObject(merged, obj1);
		extendObject(merged, obj2);

		return merged;
	}

	exports.isMapped = function (viewModel) {
		var unwrapped = ko.utils.unwrapObservable(viewModel);
		return unwrapped && unwrapped[mappingProperty];
	}

	exports.fromJS = function (jsObject /*, inputOptions, target*/ ) {
		if (arguments.length == 0) throw new Error("When calling ko.fromJS, pass the object you want to convert.");

		try {
			if (!mappingNesting++) {
				dependentObservables = [];
				visitedObjects = new objectLookup();
			}

			var options;
			var target;

			if (arguments.length == 2) {
				if (arguments[1][mappingProperty]) {
					target = arguments[1];
				} else {
					options = arguments[1];
				}
			}
			if (arguments.length == 3) {
				options = arguments[1];
				target = arguments[2];
			}

			if (target) {
				options = merge(options, target[mappingProperty]);
			}
			options = fillOptions(options);

			var result = updateViewModel(target, jsObject, options);
			if (target) {
				result = target;
			}

			// Evaluate any dependent observables that were proxied.
			// Do this after the model's observables have been created
			if (!--mappingNesting) {
				while (dependentObservables.length) {
					var DO = dependentObservables.pop();
					if (DO) {
						DO();
						
						// Move this magic property to the underlying dependent observable
						DO.__DO["throttleEvaluation"] = DO["throttleEvaluation"];
					}
				}
			}

			// Save any new mapping options in the view model, so that updateFromJS can use them later.
			result[mappingProperty] = merge(result[mappingProperty], options);

			return result;
		} catch(e) {
			mappingNesting = 0;
			throw e;
		}
	};

	exports.fromJSON = function (jsonString /*, options, target*/ ) {
		var parsed = ko.utils.parseJson(jsonString);
		arguments[0] = parsed;
		return exports.fromJS.apply(this, arguments);
	};

	exports.updateFromJS = function (viewModel) {
		throw new Error("ko.mapping.updateFromJS, use ko.mapping.fromJS instead. Please note that the order of parameters is different!");
	};

	exports.updateFromJSON = function (viewModel) {
		throw new Error("ko.mapping.updateFromJSON, use ko.mapping.fromJSON instead. Please note that the order of parameters is different!");
	};

	exports.toJS = function (rootObject, options) {
		if (!defaultOptions) exports.resetDefaultOptions();

		if (arguments.length == 0) throw new Error("When calling ko.mapping.toJS, pass the object you want to convert.");
		if (exports.getType(defaultOptions.ignore) !== "array") throw new Error("ko.mapping.defaultOptions().ignore should be an array.");
		if (exports.getType(defaultOptions.include) !== "array") throw new Error("ko.mapping.defaultOptions().include should be an array.");
		if (exports.getType(defaultOptions.copy) !== "array") throw new Error("ko.mapping.defaultOptions().copy should be an array.");

		// Merge in the options used in fromJS
		options = fillOptions(options, rootObject[mappingProperty]);

		// We just unwrap everything at every level in the object graph
		return exports.visitModel(rootObject, function (x) {
			return ko.utils.unwrapObservable(x)
		}, options);
	};

	exports.toJSON = function (rootObject, options) {
		var plainJavaScriptObject = exports.toJS(rootObject, options);
		return ko.utils.stringifyJson(plainJavaScriptObject);
	};

	exports.defaultOptions = function () {
		if (arguments.length > 0) {
			defaultOptions = arguments[0];
		} else {
			return defaultOptions;
		}
	};

	exports.resetDefaultOptions = function () {
		defaultOptions = {
			include: _defaultOptions.include.slice(0),
			ignore: _defaultOptions.ignore.slice(0),
			copy: _defaultOptions.copy.slice(0)
		};
	};

	exports.getType = function(x) {
		if ((x) && (typeof (x) === "object")) {
			if (x.constructor === Date) return "date";
			if (x.constructor === Array) return "array";
		}
		return typeof x;
	}

	function fillOptions(rawOptions, otherOptions) {
		var options = merge({}, rawOptions);

		// Move recognized root-level properties into a root namespace
		for (var i = recognizedRootProperties.length - 1; i >= 0; i--) {
			var property = recognizedRootProperties[i];
			
			// Carry on, unless this property is present
			if (!options[property]) continue;
			
			// Move the property into the root namespace
			if (!(options[""] instanceof Object)) options[""] = {};
			options[""][property] = options[property];
			delete options[property];
		}

		if (otherOptions) {
			options.ignore = mergeArrays(otherOptions.ignore, options.ignore);
			options.include = mergeArrays(otherOptions.include, options.include);
			options.copy = mergeArrays(otherOptions.copy, options.copy);
			options.observe = mergeArrays(otherOptions.observe, options.observe);
		}
		options.ignore = mergeArrays(options.ignore, defaultOptions.ignore);
		options.include = mergeArrays(options.include, defaultOptions.include);
		options.copy = mergeArrays(options.copy, defaultOptions.copy);
		options.observe = mergeArrays(options.observe, defaultOptions.observe);

		options.mappedProperties = options.mappedProperties || {};
		options.copiedProperties = options.copiedProperties || {};
		return options;
	}

	function mergeArrays(a, b) {
		if (exports.getType(a) !== "array") {
			if (exports.getType(a) === "undefined") a = [];
			else a = [a];
		}
		if (exports.getType(b) !== "array") {
			if (exports.getType(b) === "undefined") b = [];
			else b = [b];
		}

		return ko.utils.arrayGetDistinctValues(a.concat(b));
	}

	// When using a 'create' callback, we proxy the dependent observable so that it doesn't immediately evaluate on creation.
	// The reason is that the dependent observables in the user-specified callback may contain references to properties that have not been mapped yet.
	function withProxyDependentObservable(dependentObservables, callback) {
		var localDO = ko.dependentObservable;
		ko.dependentObservable = function (read, owner, options) {
			options = options || {};

			if (read && typeof read == "object") { // mirrors condition in knockout implementation of DO's
				options = read;
			}

			var realDeferEvaluation = options.deferEvaluation;

			var isRemoved = false;

			// We wrap the original dependent observable so that we can remove it from the 'dependentObservables' list we need to evaluate after mapping has
			// completed if the user already evaluated the DO themselves in the meantime.
			var wrap = function (DO) {
				// Temporarily revert ko.dependentObservable, since it is used in ko.isWriteableObservable
				var tmp = ko.dependentObservable;
				ko.dependentObservable = realKoDependentObservable;
				var isWriteable = ko.isWriteableObservable(DO);
				ko.dependentObservable = tmp;

				var wrapped = realKoDependentObservable({
					read: function () {
						if (!isRemoved) {
							ko.utils.arrayRemoveItem(dependentObservables, DO);
							isRemoved = true;
						}
						return DO.apply(DO, arguments);
					},
					write: isWriteable && function (val) {
						return DO(val);
					},
					deferEvaluation: true
				});
				if (DEBUG) wrapped._wrapper = true;
				wrapped.__DO = DO;
				return wrapped;
			};
			
			options.deferEvaluation = true; // will either set for just options, or both read/options.
			var realDependentObservable = new realKoDependentObservable(read, owner, options);

			if (!realDeferEvaluation) {
				realDependentObservable = wrap(realDependentObservable);
				dependentObservables.push(realDependentObservable);
			}

			return realDependentObservable;
		}
		ko.dependentObservable.fn = realKoDependentObservable.fn;
		ko.computed = ko.dependentObservable;
		var result = callback();
		ko.dependentObservable = localDO;
		ko.computed = ko.dependentObservable;
		return result;
	}

	function updateViewModel(mappedRootObject, rootObject, options, parentName, parent, parentPropertyName, mappedParent) {
		var isArray = exports.getType(ko.utils.unwrapObservable(rootObject)) === "array";

		parentPropertyName = parentPropertyName || "";

		// If this object was already mapped previously, take the options from there and merge them with our existing ones.
		if (exports.isMapped(mappedRootObject)) {
			var previousMapping = ko.utils.unwrapObservable(mappedRootObject)[mappingProperty];
			options = merge(previousMapping, options);
		}

		var callbackParams = {
			data: rootObject,
			parent: mappedParent || parent
		};

		var hasCreateCallback = function () {
			return options[parentName] && options[parentName].create instanceof Function;
		};

		var createCallback = function (data) {
			return withProxyDependentObservable(dependentObservables, function () {
				
				if (ko.utils.unwrapObservable(parent) instanceof Array) {
					return options[parentName].create({
						data: data || callbackParams.data,
						parent: callbackParams.parent,
						skip: emptyReturn
					});
				} else {
					return options[parentName].create({
						data: data || callbackParams.data,
						parent: callbackParams.parent
					});
				}				
			});
		};

		var hasUpdateCallback = function () {
			return options[parentName] && options[parentName].update instanceof Function;
		};

		var updateCallback = function (obj, data) {
			var params = {
				data: data || callbackParams.data,
				parent: callbackParams.parent,
				target: ko.utils.unwrapObservable(obj)
			};

			if (ko.isWriteableObservable(obj)) {
				params.observable = obj;
			}

			return options[parentName].update(params);
		}

		var alreadyMapped = visitedObjects.get(rootObject);
		if (alreadyMapped) {
			return alreadyMapped;
		}

		parentName = parentName || "";

		if (!isArray) {
			// For atomic types, do a direct update on the observable
			if (!canHaveProperties(rootObject)) {
				switch (exports.getType(rootObject)) {
				case "function":
					if (hasUpdateCallback()) {
						if (ko.isWriteableObservable(rootObject)) {
							rootObject(updateCallback(rootObject));
							mappedRootObject = rootObject;
						} else {
							mappedRootObject = updateCallback(rootObject);
						}
					} else {
						mappedRootObject = rootObject;
					}
					break;
				default:
					if (ko.isWriteableObservable(mappedRootObject)) {
						if (hasUpdateCallback()) {
							var valueToWrite = updateCallback(mappedRootObject);
							mappedRootObject(valueToWrite);
							return valueToWrite;
						} else {
							var valueToWrite = ko.utils.unwrapObservable(rootObject);
							mappedRootObject(valueToWrite);
							return valueToWrite;
						}
					} else {
						var hasCreateOrUpdateCallback = hasCreateCallback() || hasUpdateCallback();
						
						if (hasCreateCallback()) {
							mappedRootObject = createCallback();
						} else {
							mappedRootObject = ko.observable(ko.utils.unwrapObservable(rootObject));
						}

						if (hasUpdateCallback()) {
							mappedRootObject(updateCallback(mappedRootObject));
						}
						
						if (hasCreateOrUpdateCallback) return mappedRootObject;
					}
				}

			} else {
				mappedRootObject = ko.utils.unwrapObservable(mappedRootObject);
				if (!mappedRootObject) {
					if (hasCreateCallback()) {
						var result = createCallback();

						if (hasUpdateCallback()) {
							result = updateCallback(result);
						}

						return result;
					} else {
						if (hasUpdateCallback()) {
							return updateCallback(result);
						}

						mappedRootObject = {};
					}
				}

				if (hasUpdateCallback()) {
					mappedRootObject = updateCallback(mappedRootObject);
				}

				visitedObjects.save(rootObject, mappedRootObject);
				if (hasUpdateCallback()) return mappedRootObject;

				// For non-atomic types, visit all properties and update recursively
				visitPropertiesOrArrayEntries(rootObject, function (indexer) {
					var fullPropertyName = parentPropertyName.length ? parentPropertyName + "." + indexer : indexer;

					if (ko.utils.arrayIndexOf(options.ignore, fullPropertyName) != -1) {
						return;
					}

					if (ko.utils.arrayIndexOf(options.copy, fullPropertyName) != -1) {
						mappedRootObject[indexer] = rootObject[indexer];
						return;
					}

					if(typeof rootObject[indexer] != "object" && typeof rootObject[indexer] != "array" && options.observe.length > 0 && ko.utils.arrayIndexOf(options.observe, fullPropertyName) == -1)
					{
						mappedRootObject[indexer] = rootObject[indexer];
						options.copiedProperties[fullPropertyName] = true;
						return;
					}
					
					// In case we are adding an already mapped property, fill it with the previously mapped property value to prevent recursion.
					// If this is a property that was generated by fromJS, we should use the options specified there
					var prevMappedProperty = visitedObjects.get(rootObject[indexer]);
					var retval = updateViewModel(mappedRootObject[indexer], rootObject[indexer], options, indexer, mappedRootObject, fullPropertyName, mappedRootObject);
					var value = prevMappedProperty || retval;
					
					if(options.observe.length > 0 && ko.utils.arrayIndexOf(options.observe, fullPropertyName) == -1)
					{
						mappedRootObject[indexer] = ko.utils.unwrapObservable(value);
						options.copiedProperties[fullPropertyName] = true;
						return;
					}
					
					if (ko.isWriteableObservable(mappedRootObject[indexer])) {
						value = ko.utils.unwrapObservable(value);
						if (mappedRootObject[indexer]() !== value) {
							mappedRootObject[indexer](value);
						}
					} else {
						value = mappedRootObject[indexer] === undefined ? value : ko.utils.unwrapObservable(value);
						mappedRootObject[indexer] = value;
					}

					options.mappedProperties[fullPropertyName] = true;
				});
			}
		} else { //mappedRootObject is an array
			var changes = [];

			var hasKeyCallback = false;
			var keyCallback = function (x) {
				return x;
			}
			if (options[parentName] && options[parentName].key) {
				keyCallback = options[parentName].key;
				hasKeyCallback = true;
			}

			if (!ko.isObservable(mappedRootObject)) {
				// When creating the new observable array, also add a bunch of utility functions that take the 'key' of the array items into account.
				mappedRootObject = ko.observableArray([]);

				mappedRootObject.mappedRemove = function (valueOrPredicate) {
					var predicate = typeof valueOrPredicate == "function" ? valueOrPredicate : function (value) {
							return value === keyCallback(valueOrPredicate);
						};
					return mappedRootObject.remove(function (item) {
						return predicate(keyCallback(item));
					});
				}

				mappedRootObject.mappedRemoveAll = function (arrayOfValues) {
					var arrayOfKeys = filterArrayByKey(arrayOfValues, keyCallback);
					return mappedRootObject.remove(function (item) {
						return ko.utils.arrayIndexOf(arrayOfKeys, keyCallback(item)) != -1;
					});
				}

				mappedRootObject.mappedDestroy = function (valueOrPredicate) {
					var predicate = typeof valueOrPredicate == "function" ? valueOrPredicate : function (value) {
							return value === keyCallback(valueOrPredicate);
						};
					return mappedRootObject.destroy(function (item) {
						return predicate(keyCallback(item));
					});
				}

				mappedRootObject.mappedDestroyAll = function (arrayOfValues) {
					var arrayOfKeys = filterArrayByKey(arrayOfValues, keyCallback);
					return mappedRootObject.destroy(function (item) {
						return ko.utils.arrayIndexOf(arrayOfKeys, keyCallback(item)) != -1;
					});
				}

				mappedRootObject.mappedIndexOf = function (item) {
					var keys = filterArrayByKey(mappedRootObject(), keyCallback);
					var key = keyCallback(item);
					return ko.utils.arrayIndexOf(keys, key);
				}

				mappedRootObject.mappedGet = function (item) {
					return mappedRootObject()[mappedRootObject.mappedIndexOf(item)];
				}

				mappedRootObject.mappedCreate = function (value) {
					if (mappedRootObject.mappedIndexOf(value) !== -1) {
						throw new Error("There already is an object with the key that you specified.");
					}

					var item = hasCreateCallback() ? createCallback(value) : value;
					if (hasUpdateCallback()) {
						var newValue = updateCallback(item, value);
						if (ko.isWriteableObservable(item)) {
							item(newValue);
						} else {
							item = newValue;
						}
					}
					mappedRootObject.push(item);
					return item;
				}
			}

			var currentArrayKeys = filterArrayByKey(ko.utils.unwrapObservable(mappedRootObject), keyCallback).sort();
			var newArrayKeys = filterArrayByKey(rootObject, keyCallback);
			if (hasKeyCallback) newArrayKeys.sort();
			var editScript = ko.utils.compareArrays(currentArrayKeys, newArrayKeys);

			var ignoreIndexOf = {};
			
			var i, j;

			var unwrappedRootObject = ko.utils.unwrapObservable(rootObject);
			var itemsByKey = {};
			var optimizedKeys = true;
			for (i = 0, j = unwrappedRootObject.length; i < j; i++) {
				var key = keyCallback(unwrappedRootObject[i]);
				if (key === undefined || key instanceof Object) {
					optimizedKeys = false;
					break;
				}
				itemsByKey[key] = unwrappedRootObject[i];
			}

			var newContents = [];
			var passedOver = 0;
			for (i = 0, j = editScript.length; i < j; i++) {
				var key = editScript[i];
				var mappedItem;
				var fullPropertyName = parentPropertyName + "[" + i + "]";
				switch (key.status) {
				case "added":
					var item = optimizedKeys ? itemsByKey[key.value] : getItemByKey(ko.utils.unwrapObservable(rootObject), key.value, keyCallback);
					mappedItem = updateViewModel(undefined, item, options, parentName, mappedRootObject, fullPropertyName, parent);
					if(!hasCreateCallback()) {
						mappedItem = ko.utils.unwrapObservable(mappedItem);
					}

					var index = ignorableIndexOf(ko.utils.unwrapObservable(rootObject), item, ignoreIndexOf);
					
					if (mappedItem === emptyReturn) {
						passedOver++;
					} else {
						newContents[index - passedOver] = mappedItem;
					}
						
					ignoreIndexOf[index] = true;
					break;
				case "retained":
					var item = optimizedKeys ? itemsByKey[key.value] : getItemByKey(ko.utils.unwrapObservable(rootObject), key.value, keyCallback);
					mappedItem = getItemByKey(mappedRootObject, key.value, keyCallback);
					updateViewModel(mappedItem, item, options, parentName, mappedRootObject, fullPropertyName, parent);

					var index = ignorableIndexOf(ko.utils.unwrapObservable(rootObject), item, ignoreIndexOf);
					newContents[index] = mappedItem;
					ignoreIndexOf[index] = true;
					break;
				case "deleted":
					mappedItem = getItemByKey(mappedRootObject, key.value, keyCallback);
					break;
				}

				changes.push({
					event: key.status,
					item: mappedItem
				});
			}

			mappedRootObject(newContents);

			if (options[parentName] && options[parentName].arrayChanged) {
				ko.utils.arrayForEach(changes, function (change) {
					options[parentName].arrayChanged(change.event, change.item);
				});
			}
		}

		return mappedRootObject;
	}

	function ignorableIndexOf(array, item, ignoreIndices) {
		for (var i = 0, j = array.length; i < j; i++) {
			if (ignoreIndices[i] === true) continue;
			if (array[i] === item) return i;
		}
		return null;
	}

	function mapKey(item, callback) {
		var mappedItem;
		if (callback) mappedItem = callback(item);
		if (exports.getType(mappedItem) === "undefined") mappedItem = item;

		return ko.utils.unwrapObservable(mappedItem);
	}

	function getItemByKey(array, key, callback) {
		array = ko.utils.unwrapObservable(array);
		for (var i = 0, j = array.length; i < j; i++) {
			var item = array[i];
			if (mapKey(item, callback) === key) return item;
		}

		throw new Error("When calling ko.update*, the key '" + key + "' was not found!");
	}

	function filterArrayByKey(array, callback) {
		return ko.utils.arrayMap(ko.utils.unwrapObservable(array), function (item) {
			if (callback) {
				return mapKey(item, callback);
			} else {
				return item;
			}
		});
	}

	function visitPropertiesOrArrayEntries(rootObject, visitorCallback) {
		if (exports.getType(rootObject) === "array") {
			for (var i = 0; i < rootObject.length; i++)
			visitorCallback(i);
		} else {
			for (var propertyName in rootObject)
			visitorCallback(propertyName);
		}
	};

	function canHaveProperties(object) {
		var type = exports.getType(object);
		return ((type === "object") || (type === "array")) && (object !== null);
	}

	// Based on the parentName, this creates a fully classified name of a property

	function getPropertyName(parentName, parent, indexer) {
		var propertyName = parentName || "";
		if (exports.getType(parent) === "array") {
			if (parentName) {
				propertyName += "[" + indexer + "]";
			}
		} else {
			if (parentName) {
				propertyName += ".";
			}
			propertyName += indexer;
		}
		return propertyName;
	}

	exports.visitModel = function (rootObject, callback, options) {
		options = options || {};
		options.visitedObjects = options.visitedObjects || new objectLookup();

		var mappedRootObject;
		var unwrappedRootObject = ko.utils.unwrapObservable(rootObject);

		if (!canHaveProperties(unwrappedRootObject)) {
			return callback(rootObject, options.parentName);
		} else {
			options = fillOptions(options, unwrappedRootObject[mappingProperty]);

			// Only do a callback, but ignore the results
			callback(rootObject, options.parentName);
			mappedRootObject = exports.getType(unwrappedRootObject) === "array" ? [] : {};
		}

		options.visitedObjects.save(rootObject, mappedRootObject);

		var parentName = options.parentName;
		visitPropertiesOrArrayEntries(unwrappedRootObject, function (indexer) {
			if (options.ignore && ko.utils.arrayIndexOf(options.ignore, indexer) != -1) return;

			var propertyValue = unwrappedRootObject[indexer];
			options.parentName = getPropertyName(parentName, unwrappedRootObject, indexer);

			// If we don't want to explicitly copy the unmapped property...
			if (ko.utils.arrayIndexOf(options.copy, indexer) === -1) {
				// ...find out if it's a property we want to explicitly include
				if (ko.utils.arrayIndexOf(options.include, indexer) === -1) {
					// The mapped properties object contains all the properties that were part of the original object.
					// If a property does not exist, and it is not because it is part of an array (e.g. "myProp[3]"), then it should not be unmapped.
				    if (unwrappedRootObject[mappingProperty]
				        && unwrappedRootObject[mappingProperty].mappedProperties && !unwrappedRootObject[mappingProperty].mappedProperties[indexer]
				        && unwrappedRootObject[mappingProperty].copiedProperties && !unwrappedRootObject[mappingProperty].copiedProperties[indexer]
				        && !(exports.getType(unwrappedRootObject) === "array")) {
						return;
					}
				}
			}

			var outputProperty;
			switch (exports.getType(ko.utils.unwrapObservable(propertyValue))) {
			case "object":
			case "array":
			case "undefined":
				var previouslyMappedValue = options.visitedObjects.get(propertyValue);
				mappedRootObject[indexer] = (exports.getType(previouslyMappedValue) !== "undefined") ? previouslyMappedValue : exports.visitModel(propertyValue, callback, options);
				break;
			default:
				mappedRootObject[indexer] = callback(propertyValue, options.parentName);
			}
		});

		return mappedRootObject;
	}

	function simpleObjectLookup() {
		var keys = [];
		var values = [];
		this.save = function (key, value) {
			var existingIndex = ko.utils.arrayIndexOf(keys, key);
			if (existingIndex >= 0) values[existingIndex] = value;
			else {
				keys.push(key);
				values.push(value);
			}
		};
		this.get = function (key) {
			var existingIndex = ko.utils.arrayIndexOf(keys, key);
			var value = (existingIndex >= 0) ? values[existingIndex] : undefined;
			return value;
		};
	};
	
	function objectLookup() {
		var buckets = {};
		
		var findBucket = function(key) {
			var bucketKey;
			try {
				bucketKey = key;//JSON.stringify(key);
			}
			catch (e) {
				bucketKey = "$$$";
			}

			var bucket = buckets[bucketKey];
			if (bucket === undefined) {
				bucket = new simpleObjectLookup();
				buckets[bucketKey] = bucket;
			}
			return bucket;
		};
		
		this.save = function (key, value) {
			findBucket(key).save(key, value);
		};
		this.get = function (key) {
			return findBucket(key).get(key);
		};
	};
}));