68 lines
1.3 KiB
JavaScript
68 lines
1.3 KiB
JavaScript
/*
|
|
MIT License http://www.opensource.org/licenses/mit-license.php
|
|
Author Tobias Koppers @sokra
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
const TupleSet = require("./TupleSet");
|
|
|
|
/**
|
|
* @template {any[]} T
|
|
*/
|
|
class TupleQueue {
|
|
/**
|
|
* @param {Iterable<T>=} items The initial elements.
|
|
*/
|
|
constructor(items) {
|
|
/**
|
|
* @private
|
|
* @type {TupleSet<T>}
|
|
*/
|
|
this._set = new TupleSet(items);
|
|
/**
|
|
* @private
|
|
* @type {Iterator<T>}
|
|
*/
|
|
this._iterator = this._set[Symbol.iterator]();
|
|
}
|
|
|
|
/**
|
|
* Returns the number of elements in this queue.
|
|
* @returns {number} The number of elements in this queue.
|
|
*/
|
|
get length() {
|
|
return this._set.size;
|
|
}
|
|
|
|
/**
|
|
* Appends the specified element to this queue.
|
|
* @param {T} item The element to add.
|
|
* @returns {void}
|
|
*/
|
|
enqueue(...item) {
|
|
this._set.add(...item);
|
|
}
|
|
|
|
/**
|
|
* Retrieves and removes the head of this queue.
|
|
* @returns {T | undefined} The head of the queue of `undefined` if this queue is empty.
|
|
*/
|
|
dequeue() {
|
|
const result = this._iterator.next();
|
|
if (result.done) {
|
|
if (this._set.size > 0) {
|
|
this._iterator = this._set[Symbol.iterator]();
|
|
const value = this._iterator.next().value;
|
|
this._set.delete(...value);
|
|
return value;
|
|
}
|
|
return;
|
|
}
|
|
this._set.delete(...result.value);
|
|
return result.value;
|
|
}
|
|
}
|
|
|
|
module.exports = TupleQueue;
|