cloud-game/web/js/utils.js

/**
 * A decorator that passes the call to function at maximum once per specified milliseconds.
 * @param f The function to call.
 * @param ms The amount of time in milliseconds to ignore the function calls.
 * @returns {Function}
 * @example
 * const showMessage = () => { alert('00001'); }
 * const showOnlyOnceASecond = debounce(showMessage, 1000);
 */
export const debounce = (f, ms) => {
    let wait = false;

    return function () {
        if (wait) return;

        f.apply(this, arguments);
        wait = true;
        setTimeout(() => wait = false, ms);
    };
}

/**
 * A decorator that blocks and calls the last function until the specified amount of milliseconds.
 * @param f The function to call.
 * @param ms The amount of time in milliseconds to ignore the function calls.
 * @returns {Function}
 */
export const throttle = (f, ms) => {
    let lastCall;
    let lastTime;

    return function () {
        // could be a stack
        const lastContext = this;
        const lastArguments = arguments;

        if (!lastTime) {
            f.apply(lastContext, lastArguments);
            lastTime = Date.now()
        } else {
            clearTimeout(lastCall);
            lastCall = setTimeout(() => {
                if (Date.now() - lastTime >= ms) {
                    f.apply(lastContext, lastArguments);
                    lastTime = Date.now()
                }
            }, ms - (Date.now() - lastTime))
        }
    }
}