/** Defines an ADT for an ordered collection of elements with zero-based indexing.
 * @abstract
 */

class List { // eslint-disable-line no-unused-vars
    /** Creates a new, empty List object.
     * @hideconstructor
     * @abstract
     */
    constructor() {
        if (this.constructor === List) {
            throw new TypeError('Cannot create objects of abstract class List.');
        }
    }

    /** Returns the length of this List.
     * @returns {number} The number of elements stored in this List.
     * @public
     * @abstract
     */
    length() {
        throw new TypeError(`Class '${this.constructor.name}' is a subclass of 'List', and must implement abstract method '${((new Error()).stack.split('@', 1))[0]}'.`);
    }

    /** Returns an element of this List by index.