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function createQueue() {
    const queue = [];
    return {
        enqueue(item) {
            queue.unshift(item);
        },
        dequeue() {
            return queue.pop();
        },
        peek() {
            return queue[queue.length -1];
        },
        get length() {
            return queue.length;
        },
        isEmpty() {
            return queue.length === 0;
        }
    }
}

const q = createQueue();
q.enqueue(1);
q.enqueue(2);
q.enqueue(3);
q.enqueue(4);
console.log(q.isEmpty());
console.log(q.length)
console.log(q.dequeue());
console.log(q.length)
console.log(q.peek())
console.log(q.length)

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false
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3