es-next-tools/dist/structures/Stack.js

A comprehensive utility library for JavaScript and TypeScript that provides a wide range of functions for common programming tasks, including mathematical operations, date manipulations, array and object handling, string utilities, and more.

/**
 * Represents a stack data structure.
 * @template T The type of elements in the stack.
 * @example
 * const stack = new Stack<number>();
 * stack.push(1).push(2);
 * console.log(stack.pop()); // 2
 */
export class Stack {
    items = [];
    itemSet = new Set();
    /**
     * Pushes an item onto the top of the stack.
     * @param {T} item - The item to push onto the stack.
     * @returns {T} The item that was pushed.
     */
    push(item) {
        this.items.push(item);
        this.itemSet.add(item);
        return item;
    }
    /**
     * Removes and returns the item at the top of the stack.
     * @returns {T} The item at the top of the stack, or undefined if the stack is empty.
     * @throws {Error} If the stack is empty;
     */
    pop() {
        if (this.isEmpty()) {
            throw new Error('Stack is emtpy.');
        }
        const item = this.items.pop();
        if (item !== undefined)
            this.itemSet.delete(item);
        return item;
    }
    /**
     * Returns the number of items in the stack.
     * @returns {number} The size of the stack.
    */
    size() {
        return this.items.length;
    }
    /**
     * Returns the item at the top of the stack without removing it.
     * @returns {T | undefined} The item at the top of the stack, or undefined if the stack is empty.
     */
    peek() {
        return this.items[this.items.length - 1];
    }
    select(item) {
        return this.items[item];
    }
    /**
     * Checks if the stack is empty.
     * @returns {boolean} True if the stack is empty, false otherwise.
     */
    isEmpty() {
        return this.items.length === 0;
    }
    /**
     * Checks if the stack contains a specific item.
     * @param {T} item - The item to check for.
     * @returns {boolean} True if the item is in the stack, false otherwise.
     */
    contains(item) {
        return this.itemSet.has(item);
    }
}