Replacement for npm package onetime and once.

once.js

/* Copyright (c) 2020~2999 - Cologler <[email protected]> */

/**
 * Run a function exactly one time.
 *
 * @param fn {Function}
 */
function once(fn) {
    let called;
    let value;
    return function () {
        return called
            ? value
            : (called = true) && (value = fn.apply(this, arguments));
    }
}

once.ts

 /* Copyright (c) 2020~2999 - Cologler <[email protected]> */

/**
 * Run a function exactly one time.
 *
 * @param fn {Function}
 */
function once<TArgs extends any[], TResult>(fn: (...TArgs) => TResult): (...TArgs) => TResult {
    let called: boolean = false;
    let value: TResult;
    return function () {
        return called
            ? value!
            : (called = true) && (value = fn.apply(this, arguments));
    }
}