change maps to Collections

src/util/Collection.js

@@ -0,0 +1,109 @@
+/**
+ * A utility class to help make it easier to access the data stores
+ * @extends {Map}
+ */
+class Collection extends Map {
+
+  /**
+   * Returns an ordered array of the values of this collection.
+   * @returns {Array}
+   * @example
+   * // identical to:
+   * Array.from(collection.values());
+   */
+  array() {
+    return Array.from(this.values());
+  }
+
+  /**
+   * Returns the first item in this collection.
+   * @returns {Object}
+   * @example
+   * // identical to:
+   * Array.from(collection.values())[0];
+   */
+  first() {
+    return this.array()[0];
+  }
+
+  /**
+   * Returns the last item in this collection.
+   * @returns {Object}
+   */
+  last() {
+    const arr = this.array();
+    return arr[arr.length - 1];
+  }
+
+  /**
+   * Returns a random item from this collection.
+   * @returns {Object}
+   */
+  random() {
+    const arr = this.array();
+    return arr[Math.floor(Math.random() * arr.length)];
+  }
+
+  /**
+   * The length (size) of this collection.
+   * @readonly
+   */
+  get length() {
+    return this.size;
+  }
+
+  /**
+   * Returns an array of items where `item[key] === value` of the collection
+   * @param {String} key the key to filter bby
+   * @param {any} value the expected value
+   * @returns {Array<Object>}
+   * @example
+   * collection.getAll('username', 'Bob');
+   */
+  findAll(key, value) {
+    const results = [];
+    for (const item of this.array()) {
+      if (item[key] === value) {
+        results.push(item);
+      }
+    }
+    return results;
+  }
+
+  /**
+   * Returns a single item where `item[key] === value`
+   * @param {String} key the key to filter bby
+   * @param {any} value the expected value
+   * @returns {Object}
+   * @example
+   * collection.get('id', '123123...');
+   */
+  find(key, value) {
+    for (const item of this.array()) {
+      if (item[key] === value) {
+        return item;
+      }
+    }
+    return null;
+  }
+
+  /**
+   * Returns true if the collection has an item where `item[key] === value`
+   * @param {String} key the key to filter bby
+   * @param {any} value the expected value
+   * @returns {Object}
+   * @example
+   * if (collection.exists('id', '123123...')) {
+   *  console.log('user here!');
+   * }
+   */
+  exists(key, value) {
+    return Boolean(this.get(key, value));
+  }
+
+  _arrayMethod(method, args) {
+    return Array.prototype[method].apply(this.array(), args);
+  }
+}
+
+module.exports = Collection;