forerunnerdb/js/lib/KeyValueStore.js

A NoSQL document store database for browsers and Node.js.

"use strict";

var Shared = require('./Shared');

/**
 * The key value store class used when storing basic in-memory KV data,
 * and can be queried for quick retrieval. Mostly used for collection
 * primary key indexes and lookups.
 * @param {String=} name Optional KV store name.
 * @constructor
 */
var KeyValueStore = function (name) {
	this.init.apply(this, arguments);
};

KeyValueStore.prototype.init = function (name) {
	this._name = name;
	this._data = {};
	this._primaryKey = '_id';
};

Shared.addModule('KeyValueStore', KeyValueStore);
Shared.mixin(KeyValueStore.prototype, 'Mixin.ChainReactor');

/**
 * Get / set the name of the key/value store.
 * @param {String} val The name to set.
 * @returns {*}
 */
Shared.synthesize(KeyValueStore.prototype, 'name');

/**
 * Get / set the primary key.
 * @param {String} key The key to set.
 * @returns {*}
 */
KeyValueStore.prototype.primaryKey = function (key) {
	if (key !== undefined) {
		this._primaryKey = key;
		return this;
	}

	return this._primaryKey;
};

/**
 * Removes all data from the store.
 * @returns {*}
 */
KeyValueStore.prototype.truncate = function () {
	this._data = {};
	return this;
};

/**
 * Sets data against a key in the store.
 * @param {String} key The key to set data for.
 * @param {*} value The value to assign to the key.
 * @returns {*}
 */
KeyValueStore.prototype.set = function (key, value) {
	this._data[key] = value ? value : true;
	return this;
};

/**
 * Gets data stored for the passed key.
 * @param {String} key The key to get data for.
 * @returns {*}
 */
KeyValueStore.prototype.get = function (key) {
	return this._data[key];
};

/**
 * Get / set the primary key.
 * @param {*} obj A lookup query, can be a string key, an array of string keys,
 * an object with further query clauses or a regular expression that should be
 * run against all keys.
 * @returns {*}
 */
KeyValueStore.prototype.lookup = function (obj) {
	var pKeyVal = obj[this._primaryKey],
		arrIndex,
		arrCount,
		lookupItem,
		result;

	if (pKeyVal instanceof Array) {
		// An array of primary keys, find all matches
		arrCount = pKeyVal.length;
		result = [];

		for (arrIndex = 0; arrIndex < arrCount; arrIndex++) {
			lookupItem = this._data[pKeyVal[arrIndex]];

			if (lookupItem) {
				result.push(lookupItem);
			}
		}

		return result;
	} else if (pKeyVal instanceof RegExp) {
		// Create new data
		result = [];

		for (arrIndex in this._data) {
			if (this._data.hasOwnProperty(arrIndex)) {
				if (pKeyVal.test(arrIndex)) {
					result.push(this._data[arrIndex]);
				}
			}
		}

		return result;
	} else if (typeof pKeyVal === 'object') {
		// The primary key clause is an object, now we have to do some
		// more extensive searching
		if (pKeyVal.$ne) {
			// Create new data
			result = [];

			for (arrIndex in this._data) {
				if (this._data.hasOwnProperty(arrIndex)) {
					if (arrIndex !== pKeyVal.$ne) {
						result.push(this._data[arrIndex]);
					}
				}
			}

			return result;
		}

		if (pKeyVal.$in && (pKeyVal.$in instanceof Array)) {
			// Create new data
			result = [];

			for (arrIndex in this._data) {
				if (this._data.hasOwnProperty(arrIndex)) {
					if (pKeyVal.$in.indexOf(arrIndex) > -1) {
						result.push(this._data[arrIndex]);
					}
				}
			}

			return result;
		}

		if (pKeyVal.$nin && (pKeyVal.$nin instanceof Array)) {
			// Create new data
			result = [];

			for (arrIndex in this._data) {
				if (this._data.hasOwnProperty(arrIndex)) {
					if (pKeyVal.$nin.indexOf(arrIndex) === -1) {
						result.push(this._data[arrIndex]);
					}
				}
			}

			return result;
		}

		if (pKeyVal.$or && (pKeyVal.$or instanceof Array)) {
			// Create new data
			result = [];

			for (arrIndex = 0; arrIndex < pKeyVal.$or.length; arrIndex++) {
				result = result.concat(this.lookup(pKeyVal.$or[arrIndex]));
			}

			return result;
		}
	} else {
		// Key is a basic lookup from string
		lookupItem = this._data[pKeyVal];

		if (lookupItem !== undefined) {
			return [lookupItem];
		} else {
			return [];
		}
	}
};

/**
 * Removes data for the given key from the store.
 * @param {String} key The key to un-set.
 * @returns {*}
 */
KeyValueStore.prototype.unSet = function (key) {
	delete this._data[key];
	return this;
};

/**
 * Sets data for the give key in the store only where the given key
 * does not already have a value in the store.
 * @param {String} key The key to set data for.
 * @param {*} value The value to assign to the key.
 * @returns {Boolean} True if data was set or false if data already
 * exists for the key.
 */
KeyValueStore.prototype.uniqueSet = function (key, value) {
	if (this._data[key] === undefined) {
		this._data[key] = value;
		return true;
	}

	return false;
};

Shared.finishModule('KeyValueStore');
module.exports = KeyValueStore;