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- import isObject from './isObject.js';
- import now from './now.js';
- import toNumber from './toNumber.js';
- var FUNC_ERROR_TEXT = 'Expected a function';
- var nativeMax = Math.max,
- nativeMin = Math.min;
- function debounce(func, wait, options) {
- var lastArgs,
- lastThis,
- maxWait,
- result,
- timerId,
- lastCallTime,
- lastInvokeTime = 0,
- leading = false,
- maxing = false,
- trailing = true;
- if (typeof func != 'function') {
- throw new TypeError(FUNC_ERROR_TEXT);
- }
- wait = toNumber(wait) || 0;
- if (isObject(options)) {
- leading = !!options.leading;
- maxing = 'maxWait' in options;
- maxWait = maxing ? nativeMax(toNumber(options.maxWait) || 0, wait) : maxWait;
- trailing = 'trailing' in options ? !!options.trailing : trailing;
- }
- function invokeFunc(time) {
- var args = lastArgs,
- thisArg = lastThis;
- lastArgs = lastThis = undefined;
- lastInvokeTime = time;
- result = func.apply(thisArg, args);
- return result;
- }
- function leadingEdge(time) {
-
- lastInvokeTime = time;
-
- timerId = setTimeout(timerExpired, wait);
-
- return leading ? invokeFunc(time) : result;
- }
- function remainingWait(time) {
- var timeSinceLastCall = time - lastCallTime,
- timeSinceLastInvoke = time - lastInvokeTime,
- timeWaiting = wait - timeSinceLastCall;
- return maxing
- ? nativeMin(timeWaiting, maxWait - timeSinceLastInvoke)
- : timeWaiting;
- }
- function shouldInvoke(time) {
- var timeSinceLastCall = time - lastCallTime,
- timeSinceLastInvoke = time - lastInvokeTime;
-
-
-
- return (lastCallTime === undefined || (timeSinceLastCall >= wait) ||
- (timeSinceLastCall < 0) || (maxing && timeSinceLastInvoke >= maxWait));
- }
- function timerExpired() {
- var time = now();
- if (shouldInvoke(time)) {
- return trailingEdge(time);
- }
-
- timerId = setTimeout(timerExpired, remainingWait(time));
- }
- function trailingEdge(time) {
- timerId = undefined;
-
-
- if (trailing && lastArgs) {
- return invokeFunc(time);
- }
- lastArgs = lastThis = undefined;
- return result;
- }
- function cancel() {
- if (timerId !== undefined) {
- clearTimeout(timerId);
- }
- lastInvokeTime = 0;
- lastArgs = lastCallTime = lastThis = timerId = undefined;
- }
- function flush() {
- return timerId === undefined ? result : trailingEdge(now());
- }
- function debounced() {
- var time = now(),
- isInvoking = shouldInvoke(time);
- lastArgs = arguments;
- lastThis = this;
- lastCallTime = time;
- if (isInvoking) {
- if (timerId === undefined) {
- return leadingEdge(lastCallTime);
- }
- if (maxing) {
-
- clearTimeout(timerId);
- timerId = setTimeout(timerExpired, wait);
- return invokeFunc(lastCallTime);
- }
- }
- if (timerId === undefined) {
- timerId = setTimeout(timerExpired, wait);
- }
- return result;
- }
- debounced.cancel = cancel;
- debounced.flush = flush;
- return debounced;
- }
- export default debounce;
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