feat: Add core/Component.js

core/Component.js

@@ -0,0 +1,138 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2015 Famous Industries Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+'use strict';
+
+/**
+ * An abstract component meant to be subclassed.
+ *
+ * @class Component
+ * @constructor
+ * @abstract
+ *
+ * @param {Node} [node] Node to which the component should be added.
+ */
+function Component(node) {
+    /** @protected */
+    this._node = null;
+
+    /** @protected */
+    this._id = null;
+
+    /** @protected */
+    this._requestingUpdate = false;
+
+    if (node) this.onAdd(node, node.addComponent(this));
+}
+
+/**
+ * Method that will be called by the node after the component has been added
+ * to it.
+ *
+ * @method
+ * @private
+ *
+ * @param  {Node} node      Node to which the component has been added.
+ * @param  {Number} id      The id under which the component has been
+ *                          registered.
+ * @return {undefined}      undefined
+ */
+Component.prototype.onAdd = function onAdd(node, id) {
+    // Safety check needed for now to ensure backwards compatibility.
+    if (this._node === node && this._id === id) return;
+
+    if (this._node) throw new Error(
+        'Can not add component to multiple nodes.'
+    );
+
+    this._node = node;
+    this._id = id;
+};
+
+/**
+ * Method that will be called by the node after the component has been added
+ * to it.
+ *
+ * @method
+ * @private
+ *
+ * @param  {Node} node      Node from which the component has been removed.
+ * @param  {Number} id      The under which the component has previously been
+ *                          registered before being removed.
+ * @return {undefined}      undefined
+ */
+Component.prototype.onRemove = function onRemove(node, id) {
+    this._node = null;
+    this._id = null;
+};
+
+/**
+ * Requests a new update from the Node. This results into the component's
+ * `onUpdate` method being called on the next
+ *
+ * @method _requestUpdate
+ * @protected
+ *
+ * @return {undefined} undefined
+ */
+Component.prototype._requestUpdate = function _requestUpdate () {
+    if (!this._requestingUpdate && this.onUpdate) {
+        this._node.requestUpdate(this._id);
+        this._requestingUpdate = true;
+    }
+};
+
+/**
+ * A method to be invoked during the node's update phase if an update has been
+ * requested previously.
+ *
+ * @method onUpdate
+ * @private
+ *
+ * @return {undefined} undefined
+ */
+Component.prototype.onUpdate = function onUpdate () {
+    this._requestingUpdate = false;
+};
+
+/**
+ * @method
+ *
+ * @return {Node}       Node to which the component has been added.
+ */
+Component.prototype.getNode = function getNode() {
+    return this._node;
+};
+
+/**
+ * @method
+ *
+ * @return {Number}     Id assigned by the Node when the component has been
+ *                      added.
+ */
+Component.prototype.getId = function getId() {
+    return this._id;
+};
+
+module.exports = Component;