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author | Dimitri Staessens <[email protected]> | 2019-10-06 21:37:45 +0200 |
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committer | Dimitri Staessens <[email protected]> | 2019-10-06 21:37:45 +0200 |
commit | 3c51c3be85bb0d1bdb87ea0d6632f1c256912f27 (patch) | |
tree | c7ccc8279b12c4f7bdbbb4270d617e48f51722e4 /node_modules/lodash/debounce.js | |
parent | 412c104bebc507bea9c94fd53b5bdc4b64cbfe31 (diff) | |
download | website-3c51c3be85bb0d1bdb87ea0d6632f1c256912f27.tar.gz website-3c51c3be85bb0d1bdb87ea0d6632f1c256912f27.zip |
build: Add some required modules for node
Diffstat (limited to 'node_modules/lodash/debounce.js')
-rw-r--r-- | node_modules/lodash/debounce.js | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/node_modules/lodash/debounce.js b/node_modules/lodash/debounce.js new file mode 100644 index 0000000..8f751d5 --- /dev/null +++ b/node_modules/lodash/debounce.js @@ -0,0 +1,191 @@ +var isObject = require('./isObject'), + now = require('./now'), + toNumber = require('./toNumber'); + +/** Error message constants. */ +var FUNC_ERROR_TEXT = 'Expected a function'; + +/* Built-in method references for those with the same name as other `lodash` methods. */ +var nativeMax = Math.max, + nativeMin = Math.min; + +/** + * Creates a debounced function that delays invoking `func` until after `wait` + * milliseconds have elapsed since the last time the debounced function was + * invoked. 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 to the next tick, similar to `setTimeout` with a timeout of `0`. + * + * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/) + * for details over the differences between `_.debounce` and `_.throttle`. + * + * @static + * @memberOf _ + * @since 0.1.0 + * @category Function + * @param {Function} func The function to debounce. + * @param {number} [wait=0] 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 {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. + * var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 }); + * var source = new EventSource('/stream'); + * jQuery(source).on('message', debounced); + * + * // Cancel the trailing debounced invocation. + * jQuery(window).on('popstate', debounced.cancel); + */ +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) { + // Reset any `maxWait` timer. + lastInvokeTime = time; + // Start the timer for the trailing edge. + timerId = setTimeout(timerExpired, wait); + // Invoke the leading edge. + 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; + + // 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() { + var time = now(); + if (shouldInvoke(time)) { + return trailingEdge(time); + } + // Restart the timer. + timerId = setTimeout(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) { + 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) { + // Handle invocations in a tight loop. + 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; +} + +module.exports = debounce; |