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assets/js/vendor/throttle-debounce/debounce.js

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+/* eslint-disable no-undefined */
+
+import throttle from './throttle';
+
+/**
+ * Debounce execution of a function. Debouncing, unlike throttling,
+ * guarantees that a function is only executed a single time, either at the
+ * very beginning of a series of calls, or at the very end.
+ *
+ * @param  {Number}   delay         A zero-or-greater delay in milliseconds. For event callbacks, values around 100 or 250 (or even higher) are most useful.
+ * @param  {Boolean}  [atBegin]     Optional, defaults to false. If atBegin is false or unspecified, callback will only be executed `delay` milliseconds
+ *                                  after the last debounced-function call. If atBegin is true, callback will be executed only at the first debounced-function call.
+ *                                  (After the throttled-function has not been called for `delay` milliseconds, the internal counter is reset).
+ * @param  {Function} callback      A function to be executed after delay milliseconds. The `this` context and all arguments are passed through, as-is,
+ *                                  to `callback` when the debounced-function is executed.
+ *
+ * @return {Function} A new, debounced function.
+ */
+export default function ( delay, atBegin, callback ) {
+	return callback === undefined ? throttle(delay, atBegin, false) : throttle(delay, callback, atBegin !== false);
+}

assets/js/vendor/throttle-debounce/throttle.js

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+/* eslint-disable no-undefined,no-param-reassign,no-shadow */
+
+/**
+ * Throttle execution of a function. Especially useful for rate limiting
+ * execution of handlers on events like resize and scroll.
+ *
+ * @param  {Number}    delay          A zero-or-greater delay in milliseconds. For event callbacks, values around 100 or 250 (or even higher) are most useful.
+ * @param  {Boolean}   [noTrailing]   Optional, defaults to false. If noTrailing is true, callback will only execute every `delay` milliseconds while the
+ *                                    throttled-function is being called. If noTrailing is false or unspecified, callback will be executed one final time
+ *                                    after the last throttled-function call. (After the throttled-function has not been called for `delay` milliseconds,
+ *                                    the internal counter is reset)
+ * @param  {Function}  callback       A function to be executed after delay milliseconds. The `this` context and all arguments are passed through, as-is,
+ *                                    to `callback` when the throttled-function is executed.
+ * @param  {Boolean}   [debounceMode] If `debounceMode` is true (at begin), schedule `clear` to execute after `delay` ms. If `debounceMode` is false (at end),
+ *                                    schedule `callback` to execute after `delay` ms.
+ *
+ * @return {Function}  A new, throttled, function.
+ */
+export default function ( delay, noTrailing, callback, debounceMode ) {
+
+	/*
+	 * After wrapper has stopped being called, this timeout ensures that
+	 * `callback` is executed at the proper times in `throttle` and `end`
+	 * debounce modes.
+	 */
+	var timeoutID;
+	var cancelled = false;
+
+	// Keep track of the last time `callback` was executed.
+	var lastExec = 0;
+
+	// Function to clear existing timeout
+	function clearExistingTimeout () {
+		if ( timeoutID ) {
+			clearTimeout(timeoutID);
+		}
+	}
+
+	// Function to cancel next exec
+	function cancel () {
+		clearExistingTimeout();
+		cancelled = true;
+	}
+
+
+	// `noTrailing` defaults to falsy.
+	if ( typeof noTrailing !== 'boolean' ) {
+		debounceMode = callback;
+		callback = noTrailing;
+		noTrailing = undefined;
+	}
+
+	/*
+	 * The `wrapper` function encapsulates all of the throttling / debouncing
+	 * functionality and when executed will limit the rate at which `callback`
+	 * is executed.
+	 */
+	function wrapper () {
+
+		var self = this;
+		var elapsed = Date.now() - lastExec;
+		var args = arguments;
+
+		if (cancelled) {
+			return;
+		}
+
+		// Execute `callback` and update the `lastExec` timestamp.
+		function exec () {
+			lastExec = Date.now();
+			callback.apply(self, args);
+		}
+
+		/*
+		 * If `debounceMode` is true (at begin) this is used to clear the flag
+		 * to allow future `callback` executions.
+		 */
+		function clear () {
+			timeoutID = undefined;
+		}
+
+		if ( debounceMode && !timeoutID ) {
+			/*
+			 * Since `wrapper` is being called for the first time and
+			 * `debounceMode` is true (at begin), execute `callback`.
+			 */
+			exec();
+		}
+
+		clearExistingTimeout();
+
+		if ( debounceMode === undefined && elapsed > delay ) {
+			/*
+			 * In throttle mode, if `delay` time has been exceeded, execute
+			 * `callback`.
+			 */
+			exec();
+
+		} else if ( noTrailing !== true ) {
+			/*
+			 * In trailing throttle mode, since `delay` time has not been
+			 * exceeded, schedule `callback` to execute `delay` ms after most
+			 * recent execution.
+			 *
+			 * If `debounceMode` is true (at begin), schedule `clear` to execute
+			 * after `delay` ms.
+			 *
+			 * If `debounceMode` is false (at end), schedule `callback` to
+			 * execute after `delay` ms.
+			 */
+			timeoutID = setTimeout(debounceMode ? clear : exec, debounceMode === undefined ? delay - elapsed : delay);
+		}
+
+	}
+
+	wrapper.cancel = cancel;
+
+	// Return the wrapper function.
+	return wrapper;
+
+}