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build/node_modules/dbly-linked-list/lib/list-node.js

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+(function () {
+    'use strict';
+
+    /**************************************************
+     * Linked list node class
+     *
+     * Internal private class to represent a node within
+     * a linked list.  Each node has a 'data' property and
+     * a pointer the previous node and the next node in the list.
+     *
+     * Since the 'Node' function is not assigned to
+     * module.exports it is not visible outside of this
+     * file, therefore, it is private to the LinkedList
+     * class.
+     *
+     ***************************************************/
+
+    /**
+     * Creates a node object with a data property and pointer
+     * to the next node
+     *
+     * @constructor
+     * @param {object|number|string} data The data to initialize with the node
+     */
+    function Node(data) {
+        this.data = data || null;
+        this.next = null;
+        this.prev = null;
+    }
+
+    /* Functions attached to the Node prototype.  All node instances will
+     * share these methods, meaning there will NOT be copies made for each
+     * instance.  This will be a huge memory savings since there will likely
+     * be a large number of individual nodes.
+     */
+    Node.prototype = {
+
+        /**
+         * Returns whether or not the node has a pointer to the next node
+         *
+         * @returns {boolean} true if there is a next node; false otherwise
+         */
+        hasNext: function() {
+            return (this.next !== null);
+        },
+
+        /**
+         * Returns whether or not the node has a pointer to the previous node
+         *
+         * @returns {boolean} true if there is a previous node; false otherwise
+         */
+        hasPrev: function() {
+            return (this.prev !== null);
+        },
+
+        /**
+         * Returns the data of the the node
+         *
+         * @returns {object|string|number} the data of the node
+         */
+        getData: function() {
+            return this.data;
+        },
+
+        /**
+         * Returns a string represenation of the node.  If the data is an
+         * object, it returns the JSON.stringify version of the object.
+         * Otherwise, it simply returns the data
+         *
+         * @return {string} the string represenation of the node data
+         */
+        toString: function() {
+            if (typeof this.data === 'object') {
+                return JSON.stringify(this.data);
+            } else {
+                return String(this.data);
+            }
+        }
+    };
+
+    module.exports = Node;
+
+}());