@technobuddha/library/priority-queue/priority-queue.mjs

A large library of useful functions

/**
 * A simple priority queue
 */
export class PriorityQueue {
    comparator;
    /**
     * @param comparator Function to compare two elements and puts them in priority order.  Takes two elements as arguments and returns a number greater, less
     * then or equal to zero.
     * @param contents Initial contents of the queue
     */
    constructor(comparator, contents) {
        this.comparator = comparator;
        this.contents = Array.from(contents ?? []);
        this.sorted = false;
    }
    contents;
    sorted;
    sort() {
        this.contents.sort(this.comparator);
        this.sorted = true;
    }
    /**
     * Add an element to the queue
     * @param o element to be added
     */
    push(...o) {
        this.contents.push(...o);
        this.sorted = false;
    }
    /**
     * Return and remove the highest priority item from the queue
     *
     * @returns queue element
     */
    pop() {
        if (!this.sorted)
            this.sort();
        return this.contents.shift();
    }
    /**
     * Iterate through all elements in the queue
     *
     * @returns generator function
     */
    *[Symbol.iterator]() {
        if (!this.sorted)
            this.sort();
        yield* this.contents;
    }
    /**
     * Determine the number of items in the queue
     *
     * @returns number of element in the queue
     */
    get size() {
        return this.contents.length;
    }
    /**
     * Transform all elements in the queue
     *
     * @param f Function to transforme each element of the queue
     * @returns array of transformed queue elements
     */
    map(f) {
        if (!this.sorted)
            this.sort();
        // eslint-disable-next-line unicorn/no-array-callback-reference
        return this.contents.map(f);
    }
    /**
     * Change the function used to order the queue
     *
     * @param newComparator function to compare elements of the queue
     */
    reorder(newComparator) {
        this.comparator = newComparator;
        this.sorted = false;
    }
}
export default PriorityQueue;