@lesjoursfr/browser-tools/dist/throttle.js

Some browser tools for events & DOM manipulation.

/* eslint-disable @typescript-eslint/no-explicit-any */
/**
 * Based on lodash version of throttle : https://github.com/lodash/lodash/blob/master/throttle.js
 */
/**
 * Creates a debounced function that delays invoking `func` until after `wait`
 * milliseconds have elapsed since the last time the debounced function was
 * invoked, or until the next browser frame is drawn. Provide `options` to indicate
 * whether `func` should be invoked on the leading and/or trailing edge of the
 * `wait` timeout. The `func` is invoked with the last arguments provided to the
 * debounced function. Subsequent calls to the debounced function return the
 * result of the last `func` invocation.
 * **Note:** If `leading` and `trailing` options are `true`, `func` is
 * invoked on the trailing edge of the timeout only if the debounced function
 * is invoked more than once during the `wait` timeout.
 * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
 * until the next tick, similar to `setTimeout` with a timeout of `0`.
 * @param {Function} func The function to debounce
 * @param {number} wait The number of milliseconds to delay
 * @param {Object} [options={}] The options object
 * @param {boolean} [options.leading=false] Specify invoking on the leading edge of the timeout
 * @param {boolean} [options.trailing=true] Specify invoking on the trailing edge of the timeout
 * @param {number} [options.maxWait] The maximum time `func` is allowed to be delayed before it's invoked
 * @returns {Function} Returns the new debounced function
 */
function debounce(func, wait, options = {}) {
    let lastArgs, lastThis, result, timerId, lastCallTime;
    let lastInvokeTime = 0;
    const leading = !!options.leading;
    const maxing = "maxWait" in options;
    const maxWait = maxing ? Math.max(options.maxWait || 0, wait) : undefined;
    const trailing = "trailing" in options ? !!options.trailing : true;
    function invokeFunc(time) {
        const args = lastArgs;
        const thisArg = lastThis;
        lastArgs = lastThis = undefined;
        lastInvokeTime = time;
        result = func.apply(thisArg, args);
        return result;
    }
    function startTimer(pendingFunc, wait) {
        return setTimeout(pendingFunc, wait);
    }
    function leadingEdge(time) {
        // Reset any `maxWait` timer.
        lastInvokeTime = time;
        // Start the timer for the trailing edge.
        timerId = startTimer(timerExpired, wait);
        // Invoke the leading edge.
        return leading ? invokeFunc(time) : result;
    }
    function remainingWait(time) {
        const timeSinceLastCall = time - lastCallTime;
        const timeSinceLastInvoke = time - lastInvokeTime;
        const timeWaiting = wait - timeSinceLastCall;
        return maxing ? Math.min(timeWaiting, maxWait - timeSinceLastInvoke) : timeWaiting;
    }
    function shouldInvoke(time) {
        const timeSinceLastCall = time - lastCallTime;
        const timeSinceLastInvoke = time - lastInvokeTime;
        // Either this is the first call, activity has stopped and we're at the
        // trailing edge, the system time has gone backwards and we're treating
        // it as the trailing edge, or we've hit the `maxWait` limit.
        return (lastCallTime === undefined ||
            timeSinceLastCall >= wait ||
            timeSinceLastCall < 0 ||
            (maxing && timeSinceLastInvoke >= maxWait));
    }
    function timerExpired() {
        const time = Date.now();
        if (shouldInvoke(time)) {
            return trailingEdge(time);
        }
        // Restart the timer.
        timerId = startTimer(timerExpired, remainingWait(time));
    }
    function trailingEdge(time) {
        timerId = undefined;
        // Only invoke if we have `lastArgs` which means `func` has been
        // debounced at least once.
        if (trailing && lastArgs) {
            return invokeFunc(time);
        }
        lastArgs = lastThis = undefined;
        return result;
    }
    function debounced(...args) {
        const time = Date.now();
        const isInvoking = shouldInvoke(time);
        lastArgs = args;
        // eslint-disable-next-line @typescript-eslint/no-this-alias
        lastThis = this;
        lastCallTime = time;
        if (isInvoking) {
            if (timerId === undefined) {
                return leadingEdge(lastCallTime);
            }
            if (maxing) {
                // Handle invocations in a tight loop.
                timerId = startTimer(timerExpired, wait);
                return invokeFunc(lastCallTime);
            }
        }
        if (timerId === undefined) {
            timerId = startTimer(timerExpired, wait);
        }
        return result;
    }
    return debounced;
}
/**
 * Creates a throttled function that only invokes `func` at most once per
 * every `wait` milliseconds (or once per browser frame). Provide `options` to indicate
 * whether `func` should be invoked on the leading and/or trailing edge of the
 * `wait` timeout. The `func` is invoked with the last arguments provided to the
 * throttled function. Subsequent calls to the throttled function return the
 * result of the last `func` invocation.
 * **Note:** If `leading` and `trailing` options are `true`, `func` is
 * invoked on the trailing edge of the timeout only if the throttled function
 * is invoked more than once during the `wait` timeout.
 * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
 * until the next tick, similar to `setTimeout` with a timeout of `0`.
 * @param {Function} func The function to throttle
 * @param {number} wait The number of milliseconds to throttle invocations to
 * @param {Object} [options={}] The options object
 * @param {boolean} [options.leading=true] Specify invoking on the leading edge of the timeout
 * @param {boolean} [options.trailing=true] Specify invoking on the trailing edge of the timeout
 * @returns {Function} Returns the new throttled function
 */
function throttle(func, wait, options = {}) {
    const leading = "leading" in options ? !!options.leading : true;
    const trailing = "trailing" in options ? !!options.trailing : true;
    return debounce(func, wait, {
        leading,
        trailing,
        maxWait: wait,
    });
}
export { debounce, throttle };