--- /dev/null
+var isObject = require('../lang/isObject'),
+ now = require('../date/now');
+
+/** Used as the `TypeError` message for "Functions" methods. */
+var FUNC_ERROR_TEXT = 'Expected a function';
+
+/* Native method references for those with the same name as other `lodash` methods. */
+var nativeMax = Math.max;
+
+/**
+ * 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 invocations. Provide an options object to indicate that `func`
+ * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+ * 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 the debounced function is
+ * invoked more than once during the `wait` timeout.
+ *
+ * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+ * for details over the differences between `_.debounce` and `_.throttle`.
+ *
+ * @static
+ * @memberOf _
+ * @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 the click event is fired, debouncing subsequent calls
+ * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
+ * 'leading': true,
+ * 'trailing': false
+ * }));
+ *
+ * // ensure `batchLog` is invoked once after 1 second of debounced calls
+ * var source = new EventSource('/stream');
+ * jQuery(source).on('message', _.debounce(batchLog, 250, {
+ * 'maxWait': 1000
+ * }));
+ *
+ * // cancel a debounced call
+ * var todoChanges = _.debounce(batchLog, 1000);
+ * Object.observe(models.todo, todoChanges);
+ *
+ * Object.observe(models, function(changes) {
+ * if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
+ * todoChanges.cancel();
+ * }
+ * }, ['delete']);
+ *
+ * // ...at some point `models.todo` is changed
+ * models.todo.completed = true;
+ *
+ * // ...before 1 second has passed `models.todo` is deleted
+ * // which cancels the debounced `todoChanges` call
+ * delete models.todo;
+ */
+function debounce(func, wait, options) {
+ var args,
+ maxTimeoutId,
+ result,
+ stamp,
+ thisArg,
+ timeoutId,
+ trailingCall,
+ lastCalled = 0,
+ maxWait = false,
+ trailing = true;
+
+ if (typeof func != 'function') {
+ throw new TypeError(FUNC_ERROR_TEXT);
+ }
+ wait = wait < 0 ? 0 : (+wait || 0);
+ if (options === true) {
+ var leading = true;
+ trailing = false;
+ } else if (isObject(options)) {
+ leading = !!options.leading;
+ maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
+ trailing = 'trailing' in options ? !!options.trailing : trailing;
+ }
+
+ function cancel() {
+ if (timeoutId) {
+ clearTimeout(timeoutId);
+ }
+ if (maxTimeoutId) {
+ clearTimeout(maxTimeoutId);
+ }
+ lastCalled = 0;
+ maxTimeoutId = timeoutId = trailingCall = undefined;
+ }
+
+ function complete(isCalled, id) {
+ if (id) {
+ clearTimeout(id);
+ }
+ maxTimeoutId = timeoutId = trailingCall = undefined;
+ if (isCalled) {
+ lastCalled = now();
+ result = func.apply(thisArg, args);
+ if (!timeoutId && !maxTimeoutId) {
+ args = thisArg = undefined;
+ }
+ }
+ }
+
+ function delayed() {
+ var remaining = wait - (now() - stamp);
+ if (remaining <= 0 || remaining > wait) {
+ complete(trailingCall, maxTimeoutId);
+ } else {
+ timeoutId = setTimeout(delayed, remaining);
+ }
+ }
+
+ function maxDelayed() {
+ complete(trailing, timeoutId);
+ }
+
+ function debounced() {
+ args = arguments;
+ stamp = now();
+ thisArg = this;
+ trailingCall = trailing && (timeoutId || !leading);
+
+ if (maxWait === false) {
+ var leadingCall = leading && !timeoutId;
+ } else {
+ if (!maxTimeoutId && !leading) {
+ lastCalled = stamp;
+ }
+ var remaining = maxWait - (stamp - lastCalled),
+ isCalled = remaining <= 0 || remaining > maxWait;
+
+ if (isCalled) {
+ if (maxTimeoutId) {
+ maxTimeoutId = clearTimeout(maxTimeoutId);
+ }
+ lastCalled = stamp;
+ result = func.apply(thisArg, args);
+ }
+ else if (!maxTimeoutId) {
+ maxTimeoutId = setTimeout(maxDelayed, remaining);
+ }
+ }
+ if (isCalled && timeoutId) {
+ timeoutId = clearTimeout(timeoutId);
+ }
+ else if (!timeoutId && wait !== maxWait) {
+ timeoutId = setTimeout(delayed, wait);
+ }
+ if (leadingCall) {
+ isCalled = true;
+ result = func.apply(thisArg, args);
+ }
+ if (isCalled && !timeoutId && !maxTimeoutId) {
+ args = thisArg = undefined;
+ }
+ return result;
+ }
+ debounced.cancel = cancel;
+ return debounced;
+}
+
+module.exports = debounce;
projects / yaffs-website / blobdiff