hd-utils
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A handy utils for modern JS developers
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JavaScript
//@ts-nocheck
import getGlobalThis from '../general/getGlobalThis';
import isObject from '../validation/isObject';
/**
* 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. The debounced function
* comes with a `cancel` method to cancel delayed `func` invocations and a
* `flush` method to immediately invoke them. 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`.
*
* If `wait` is omitted in an environment with `requestAnimationFrame`, `func`
* invocation will be deferred until the next frame is drawn (typically about
* 16ms).
*
* See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
* for details over the differences between `debounce` and `throttle`.
*
* @since 0.1.0
* @category Function
* @param {Function} func The function to debounce.
* @param {number} [wait=0]
* The number of milliseconds to delay; if omitted, `requestAnimationFrame` is
* used (if available).
* @param {Object} [options={}] The options object.
* @param {boolean} [options.leading=false]
* Specify invoking on the leading edge of the timeout.
* @param {number} [options.maxWait]
* The maximum time `func` is allowed to be delayed before it's invoked.
* @param {boolean} [options.trailing=true]
* Specify invoking on the trailing edge of the timeout.
* @returns {Function} Returns the new debounced function.
* @example
*
* // Avoid costly calculations while the window size is in flux.
* jQuery(window).on('resize', debounce(calculateLayout, 150))
*
* // Invoke `sendMail` when clicked, debouncing subsequent calls.
* jQuery(element).on('click', debounce(sendMail, 300, {
* 'leading': true,
* 'trailing': false
* }))
*
* // Ensure `batchLog` is invoked once after 1 second of debounced calls.
* const debounced = debounce(batchLog, 250, { 'maxWait': 1000 })
* const source = new EventSource('/stream')
* jQuery(source).on('message', debounced)
*
* // Cancel the trailing debounced invocation.
* jQuery(window).on('popstate', debounced.cancel)
*
* // Check for pending invocations.
* const status = debounced.pending() ? "Pending..." : "Ready"
*/
function debounce(func, wait = 200, options) {
let lastArgs, lastThis, maxWait, result, timerId, lastCallTime;
const root = getGlobalThis();
let lastInvokeTime = 0;
let leading = false;
let maxing = false;
let trailing = true;
// Bypass `requestAnimationFrame` by explicitly setting `wait=0`.
const useRAF = !wait && wait !== 0 && typeof root.requestAnimationFrame === 'function';
if (typeof func !== 'function') {
throw new TypeError('Expected a function');
}
wait = +wait || 0;
if (isObject(options)) {
leading = !!options.leading;
maxing = 'maxWait' in options;
maxWait = maxing ? Math.max(+options.maxWait || 0, wait) : maxWait;
trailing = 'trailing' in options ? !!options.trailing : trailing;
}
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) {
if (useRAF) {
root.cancelAnimationFrame(timerId);
return root.requestAnimationFrame(pendingFunc);
}
return setTimeout(pendingFunc, wait);
}
function cancelTimer(id) {
if (useRAF) {
return root.cancelAnimationFrame(id);
}
clearTimeout(id);
}
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 cancel() {
if (timerId !== undefined) {
cancelTimer(timerId);
}
lastInvokeTime = 0;
lastArgs = lastCallTime = lastThis = timerId = undefined;
}
function flush() {
return timerId === undefined ? result : trailingEdge(Date.now());
}
function pending() {
return timerId !== undefined;
}
function debounced(...args) {
const time = Date.now();
const isInvoking = shouldInvoke(time);
lastArgs = args;
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;
}
debounced.cancel = cancel;
debounced.flush = flush;
debounced.pending = pending;
return debounced;
}
export default debounce;