init

lib/durandal/js/plugins/serializer.js

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+/**
+ * Durandal 2.1.0 Copyright (c) 2012 Blue Spire Consulting, Inc. All Rights Reserved.
+ * Available via the MIT license.
+ * see: http://durandaljs.com or https://github.com/BlueSpire/Durandal for details.
+ */
+/**
+ * Serializes and deserializes data to/from JSON.
+ * @module serializer
+ * @requires system
+ */
+define(['durandal/system'], function(system) {
+    /**
+     * @class SerializerModule
+     * @static
+     */
+    return {
+        /**
+         * The name of the attribute that the serializer should use to identify an object's type.
+         * @property {string} typeAttribute
+         * @default type
+         */
+        typeAttribute: 'type',
+        /**
+         * The amount of space to use for indentation when writing out JSON.
+         * @property {string|number} space
+         * @default undefined
+         */
+        space:undefined,
+        /**
+         * The default replacer function used during serialization. By default properties starting with '_' or '$' are removed from the serialized object.
+         * @method replacer
+         * @param {string} key The object key to check.
+         * @param {object} value The object value to check.
+         * @return {object} The value to serialize.
+         */
+        replacer: function(key, value) {
+            if(key){
+                var first = key[0];
+                if(first === '_' || first === '$'){
+                    return undefined;
+                }
+            }
+
+            return value;
+        },
+        /**
+         * Serializes the object.
+         * @method serialize
+         * @param {object} object The object to serialize.
+         * @param {object} [settings] Settings can specify a replacer or space to override the serializer defaults.
+         * @return {string} The JSON string.
+         */
+        serialize: function(object, settings) {
+            settings = (settings === undefined) ? {} : settings;
+
+            if(system.isString(settings) || system.isNumber(settings)) {
+                settings = { space: settings };
+            }
+
+            return JSON.stringify(object, settings.replacer || this.replacer, settings.space || this.space);
+        },
+        /**
+         * Gets the type id for an object instance, using the configured `typeAttribute`.
+         * @method getTypeId
+         * @param {object} object The object to serialize.
+         * @return {string} The type.
+         */
+        getTypeId: function(object) {
+            if (object) {
+                return object[this.typeAttribute];
+            }
+
+            return undefined;
+        },
+        /**
+         * Maps type ids to object constructor functions. Keys are type ids and values are functions.
+         * @property {object} typeMap.
+         */
+        typeMap: {},
+        /**
+         * Adds a type id/constructor function mampping to the `typeMap`.
+         * @method registerType
+         * @param {string} typeId The type id.
+         * @param {function} constructor The constructor.
+         */
+        registerType: function() {
+            var first = arguments[0];
+
+            if (arguments.length == 1) {
+                var id = first[this.typeAttribute] || system.getModuleId(first);
+                this.typeMap[id] = first;
+            } else {
+                this.typeMap[first] = arguments[1];
+            }
+        },
+        /**
+         * The default reviver function used during deserialization. By default is detects type properties on objects and uses them to re-construct the correct object using the provided constructor mapping.
+         * @method reviver
+         * @param {string} key The attribute key.
+         * @param {object} value The object value associated with the key.
+         * @param {function} getTypeId A custom function used to get the type id from a value.
+         * @param {object} getConstructor A custom function used to get the constructor function associated with a type id.
+         * @return {object} The value.
+         */
+        reviver: function(key, value, getTypeId, getConstructor) {
+            var typeId = getTypeId(value);
+            if (typeId) {
+                var ctor = getConstructor(typeId);
+                if (ctor) {
+                    if (ctor.fromJSON) {
+                        return ctor.fromJSON(value);
+                    }
+
+                    return new ctor(value);
+                }
+            }
+
+            return value;
+        },
+        /**
+         * Deserialize the JSON.
+         * @method deserialize
+         * @param {string} text The JSON string.
+         * @param {object} [settings] Settings can specify a reviver, getTypeId function or getConstructor function.
+         * @return {object} The deserialized object.
+         */
+        deserialize: function(text, settings) {
+            var that = this;
+            settings = settings || {};
+
+            var getTypeId = settings.getTypeId || function(object) { return that.getTypeId(object); };
+            var getConstructor = settings.getConstructor || function(id) { return that.typeMap[id]; };
+            var reviver = settings.reviver || function(key, value) { return that.reviver(key, value, getTypeId, getConstructor); };
+
+            return JSON.parse(text, reviver);
+        },
+        /**
+         * Clone the object.
+         * @method clone
+         * @param {object} obj The object to clone.
+         * @param {object} [settings] Settings can specify any of the options allowed by the serialize or deserialize methods.
+         * @return {object} The new clone.
+         */
+        clone:function(obj, settings) {
+            return this.deserialize(this.serialize(obj, settings), settings);
+        }
+    };
+});