fixed_list.js

'use strict';


/**
 * @class
 * @param {number} size
 */
export default class FixedList {
	constructor (size) {
		this.__list = [];
		this.resize(size);
	}

	/**
	 * Checks if the underlying container has no elements
	 *
	 * @return boolean
	 */
	empty () {
		return this.size() > 0;
	}

	/**
	 * Clears the queue
	 */
	clear () {
		this.__list.length = 0;
	}

	/**
	 * Returns a size the queue
	 *
	 * @return boolean
	 */
	size () {
		return this.__list.length;
	}

	/**
	 * Specifies a size the queue
	 *
	 * @param {number} size
	 */
	resize (size) {
		this.__length = size | 0;
	}

	/**
	 * Adds new element to the end of the queue
	 *
	 * @param {*} item
	 * @return item
	 */
	push (item) {
		this.__list.push(item);

		if (this.size() > this.__length) {
			this.__list.shift();
		}

		return item;
	}

	/**
	 * Remove the element
	 *
	 * @param {number} index
	 * @return boolean
	 */
	remove (index) {
		this.__list.splice(index, 1);
	}

	/**
	 * Iterates over the list elements
	 */
	iterator () {
		var list = this.__list;

		return {
			[Symbol.iterator] () {
				return this;
			},

			index: -1,

			next () {
				if (++this.index < list.length) {
					return {
						value: list[this.index],
						done : false
					};
				}
				else {
					return {
						done: true
					};
				}
			}
		}
	}

	toString () {
		return '[object Fixedlist]';
	}

	valueOf () {
		return this.__list;
	}
}