data-structures-and-algorithms/deque

import {IndexError} from '@failure-abstraction/error';

import Deque from './Deque.js';

/**
 * EmptyDeque.
 *
 * @param {Iterable<any>} iterable
 */
export default function EmptyDeque(iterable) {
    if (iterable !== null) {
        this.extend(iterable);
    }
}

EmptyDeque.prototype = new Deque();

EmptyDeque.prototype.len = function () {
    return 0;
};

EmptyDeque.prototype.capacity = function () {
    return 0;
};

EmptyDeque.prototype.values = function () {
    return {
        next() {
            return {done: true};
        },
    };
};

EmptyDeque.prototype.append = function (_x) {
    return this;
};

EmptyDeque.prototype.appendleft = function (_x) {
    return this;
};

EmptyDeque.prototype.clear = function () {
    return this;
};

EmptyDeque.prototype.copy = function () {
    return new EmptyDeque(this);
};

EmptyDeque.prototype._where = function (i) {
    throw new IndexError(i);
};

EmptyDeque.prototype.pop =
    // eslint-disable-next-line no-multi-assign
    EmptyDeque.prototype.popleft = function () {
        throw new IndexError('pop / popleft');
    };