es-next-tools/dist/function/once.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.

/**
 * Creates a function that is restricted to invoking the original function only once.
 * @param {T} fn - The function to restrict.
 * @returns {T} The new restricted function.
 * @template T
 * @example
 * let count = 0;
 * const incrementOnce = once(() => ++count);
 * console.log(incrementOnce()); // 1
 * console.log(incrementOnce()); // 1
 * console.log(count); // 1
 */
export function once(fn) {
    let hasRun = false;
    let result;
    return ((...args) => {
        if (!hasRun) {
            hasRun = true;
            result = fn(...args);
        }
        return result;
    });
}