Permalink
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
* lint files * added back arrow-paren and removed duplicate
213 lines (190 sloc)
6.55 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import isObject from './isObject.js' | |
| import root from './.internal/root.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. 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, options) { | |
| let lastArgs, | |
| lastThis, | |
| maxWait, | |
| result, | |
| timerId, | |
| lastCallTime | |
| 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 |