rot-js/lib/eventqueue.js

A roguelike toolkit in JavaScript

import { MinHeap } from "./MinHeap.js";
export default class EventQueue {
    /**
     * @class Generic event queue: stores events and retrieves them based on their time
     */
    constructor() {
        this._time = 0;
        this._events = new MinHeap();
    }
    /**
     * @returns {number} Elapsed time
     */
    getTime() { return this._time; }
    /**
     * Clear all scheduled events
     */
    clear() {
        this._events = new MinHeap();
        return this;
    }
    /**
     * @param {?} event
     * @param {number} time
     */
    add(event, time) {
        this._events.push(event, time);
    }
    /**
     * Locates the nearest event, advances time if necessary. Returns that event and removes it from the queue.
     * @returns {? || null} The event previously added by addEvent, null if no event available
     */
    get() {
        if (!this._events.len()) {
            return null;
        }
        let { key: time, value: event } = this._events.pop();
        if (time > 0) { /* advance */
            this._time += time;
            this._events.shift(-time);
        }
        return event;
    }
    /**
     * Get the time associated with the given event
     * @param {?} event
     * @returns {number} time
     */
    getEventTime(event) {
        const r = this._events.find(event);
        if (r) {
            const { key } = r;
            return key;
        }
        return undefined;
    }
    /**
     * Remove an event from the queue
     * @param {?} event
     * @returns {bool} success?
     */
    remove(event) {
        return this._events.remove(event);
    }
    ;
}