source: trip-planner-front/node_modules/lodash.debounce/index.js@ fa375fe

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1/**
2 * lodash (Custom Build) <https://lodash.com/>
3 * Build: `lodash modularize exports="npm" -o ./`
4 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
5 * Released under MIT license <https://lodash.com/license>
6 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
7 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
8 */
9
10/** Used as the `TypeError` message for "Functions" methods. */
11var FUNC_ERROR_TEXT = 'Expected a function';
12
13/** Used as references for various `Number` constants. */
14var NAN = 0 / 0;
15
16/** `Object#toString` result references. */
17var symbolTag = '[object Symbol]';
18
19/** Used to match leading and trailing whitespace. */
20var reTrim = /^\s+|\s+$/g;
21
22/** Used to detect bad signed hexadecimal string values. */
23var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;
24
25/** Used to detect binary string values. */
26var reIsBinary = /^0b[01]+$/i;
27
28/** Used to detect octal string values. */
29var reIsOctal = /^0o[0-7]+$/i;
30
31/** Built-in method references without a dependency on `root`. */
32var freeParseInt = parseInt;
33
34/** Detect free variable `global` from Node.js. */
35var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;
36
37/** Detect free variable `self`. */
38var freeSelf = typeof self == 'object' && self && self.Object === Object && self;
39
40/** Used as a reference to the global object. */
41var root = freeGlobal || freeSelf || Function('return this')();
42
43/** Used for built-in method references. */
44var objectProto = Object.prototype;
45
46/**
47 * Used to resolve the
48 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
49 * of values.
50 */
51var objectToString = objectProto.toString;
52
53/* Built-in method references for those with the same name as other `lodash` methods. */
54var nativeMax = Math.max,
55 nativeMin = Math.min;
56
57/**
58 * Gets the timestamp of the number of milliseconds that have elapsed since
59 * the Unix epoch (1 January 1970 00:00:00 UTC).
60 *
61 * @static
62 * @memberOf _
63 * @since 2.4.0
64 * @category Date
65 * @returns {number} Returns the timestamp.
66 * @example
67 *
68 * _.defer(function(stamp) {
69 * console.log(_.now() - stamp);
70 * }, _.now());
71 * // => Logs the number of milliseconds it took for the deferred invocation.
72 */
73var now = function() {
74 return root.Date.now();
75};
76
77/**
78 * Creates a debounced function that delays invoking `func` until after `wait`
79 * milliseconds have elapsed since the last time the debounced function was
80 * invoked. The debounced function comes with a `cancel` method to cancel
81 * delayed `func` invocations and a `flush` method to immediately invoke them.
82 * Provide `options` to indicate whether `func` should be invoked on the
83 * leading and/or trailing edge of the `wait` timeout. The `func` is invoked
84 * with the last arguments provided to the debounced function. Subsequent
85 * calls to the debounced function return the result of the last `func`
86 * invocation.
87 *
88 * **Note:** If `leading` and `trailing` options are `true`, `func` is
89 * invoked on the trailing edge of the timeout only if the debounced function
90 * is invoked more than once during the `wait` timeout.
91 *
92 * If `wait` is `0` and `leading` is `false`, `func` invocation is deferred
93 * until to the next tick, similar to `setTimeout` with a timeout of `0`.
94 *
95 * See [David Corbacho's article](https://css-tricks.com/debouncing-throttling-explained-examples/)
96 * for details over the differences between `_.debounce` and `_.throttle`.
97 *
98 * @static
99 * @memberOf _
100 * @since 0.1.0
101 * @category Function
102 * @param {Function} func The function to debounce.
103 * @param {number} [wait=0] The number of milliseconds to delay.
104 * @param {Object} [options={}] The options object.
105 * @param {boolean} [options.leading=false]
106 * Specify invoking on the leading edge of the timeout.
107 * @param {number} [options.maxWait]
108 * The maximum time `func` is allowed to be delayed before it's invoked.
109 * @param {boolean} [options.trailing=true]
110 * Specify invoking on the trailing edge of the timeout.
111 * @returns {Function} Returns the new debounced function.
112 * @example
113 *
114 * // Avoid costly calculations while the window size is in flux.
115 * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
116 *
117 * // Invoke `sendMail` when clicked, debouncing subsequent calls.
118 * jQuery(element).on('click', _.debounce(sendMail, 300, {
119 * 'leading': true,
120 * 'trailing': false
121 * }));
122 *
123 * // Ensure `batchLog` is invoked once after 1 second of debounced calls.
124 * var debounced = _.debounce(batchLog, 250, { 'maxWait': 1000 });
125 * var source = new EventSource('/stream');
126 * jQuery(source).on('message', debounced);
127 *
128 * // Cancel the trailing debounced invocation.
129 * jQuery(window).on('popstate', debounced.cancel);
130 */
131function debounce(func, wait, options) {
132 var lastArgs,
133 lastThis,
134 maxWait,
135 result,
136 timerId,
137 lastCallTime,
138 lastInvokeTime = 0,
139 leading = false,
140 maxing = false,
141 trailing = true;
142
143 if (typeof func != 'function') {
144 throw new TypeError(FUNC_ERROR_TEXT);
145 }
146 wait = toNumber(wait) || 0;
147 if (isObject(options)) {
148 leading = !!options.leading;
149 maxing = 'maxWait' in options;
150 maxWait = maxing ? nativeMax(toNumber(options.maxWait) || 0, wait) : maxWait;
151 trailing = 'trailing' in options ? !!options.trailing : trailing;
152 }
153
154 function invokeFunc(time) {
155 var args = lastArgs,
156 thisArg = lastThis;
157
158 lastArgs = lastThis = undefined;
159 lastInvokeTime = time;
160 result = func.apply(thisArg, args);
161 return result;
162 }
163
164 function leadingEdge(time) {
165 // Reset any `maxWait` timer.
166 lastInvokeTime = time;
167 // Start the timer for the trailing edge.
168 timerId = setTimeout(timerExpired, wait);
169 // Invoke the leading edge.
170 return leading ? invokeFunc(time) : result;
171 }
172
173 function remainingWait(time) {
174 var timeSinceLastCall = time - lastCallTime,
175 timeSinceLastInvoke = time - lastInvokeTime,
176 result = wait - timeSinceLastCall;
177
178 return maxing ? nativeMin(result, maxWait - timeSinceLastInvoke) : result;
179 }
180
181 function shouldInvoke(time) {
182 var timeSinceLastCall = time - lastCallTime,
183 timeSinceLastInvoke = time - lastInvokeTime;
184
185 // Either this is the first call, activity has stopped and we're at the
186 // trailing edge, the system time has gone backwards and we're treating
187 // it as the trailing edge, or we've hit the `maxWait` limit.
188 return (lastCallTime === undefined || (timeSinceLastCall >= wait) ||
189 (timeSinceLastCall < 0) || (maxing && timeSinceLastInvoke >= maxWait));
190 }
191
192 function timerExpired() {
193 var time = now();
194 if (shouldInvoke(time)) {
195 return trailingEdge(time);
196 }
197 // Restart the timer.
198 timerId = setTimeout(timerExpired, remainingWait(time));
199 }
200
201 function trailingEdge(time) {
202 timerId = undefined;
203
204 // Only invoke if we have `lastArgs` which means `func` has been
205 // debounced at least once.
206 if (trailing && lastArgs) {
207 return invokeFunc(time);
208 }
209 lastArgs = lastThis = undefined;
210 return result;
211 }
212
213 function cancel() {
214 if (timerId !== undefined) {
215 clearTimeout(timerId);
216 }
217 lastInvokeTime = 0;
218 lastArgs = lastCallTime = lastThis = timerId = undefined;
219 }
220
221 function flush() {
222 return timerId === undefined ? result : trailingEdge(now());
223 }
224
225 function debounced() {
226 var time = now(),
227 isInvoking = shouldInvoke(time);
228
229 lastArgs = arguments;
230 lastThis = this;
231 lastCallTime = time;
232
233 if (isInvoking) {
234 if (timerId === undefined) {
235 return leadingEdge(lastCallTime);
236 }
237 if (maxing) {
238 // Handle invocations in a tight loop.
239 timerId = setTimeout(timerExpired, wait);
240 return invokeFunc(lastCallTime);
241 }
242 }
243 if (timerId === undefined) {
244 timerId = setTimeout(timerExpired, wait);
245 }
246 return result;
247 }
248 debounced.cancel = cancel;
249 debounced.flush = flush;
250 return debounced;
251}
252
253/**
254 * Checks if `value` is the
255 * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
256 * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
257 *
258 * @static
259 * @memberOf _
260 * @since 0.1.0
261 * @category Lang
262 * @param {*} value The value to check.
263 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
264 * @example
265 *
266 * _.isObject({});
267 * // => true
268 *
269 * _.isObject([1, 2, 3]);
270 * // => true
271 *
272 * _.isObject(_.noop);
273 * // => true
274 *
275 * _.isObject(null);
276 * // => false
277 */
278function isObject(value) {
279 var type = typeof value;
280 return !!value && (type == 'object' || type == 'function');
281}
282
283/**
284 * Checks if `value` is object-like. A value is object-like if it's not `null`
285 * and has a `typeof` result of "object".
286 *
287 * @static
288 * @memberOf _
289 * @since 4.0.0
290 * @category Lang
291 * @param {*} value The value to check.
292 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
293 * @example
294 *
295 * _.isObjectLike({});
296 * // => true
297 *
298 * _.isObjectLike([1, 2, 3]);
299 * // => true
300 *
301 * _.isObjectLike(_.noop);
302 * // => false
303 *
304 * _.isObjectLike(null);
305 * // => false
306 */
307function isObjectLike(value) {
308 return !!value && typeof value == 'object';
309}
310
311/**
312 * Checks if `value` is classified as a `Symbol` primitive or object.
313 *
314 * @static
315 * @memberOf _
316 * @since 4.0.0
317 * @category Lang
318 * @param {*} value The value to check.
319 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
320 * @example
321 *
322 * _.isSymbol(Symbol.iterator);
323 * // => true
324 *
325 * _.isSymbol('abc');
326 * // => false
327 */
328function isSymbol(value) {
329 return typeof value == 'symbol' ||
330 (isObjectLike(value) && objectToString.call(value) == symbolTag);
331}
332
333/**
334 * Converts `value` to a number.
335 *
336 * @static
337 * @memberOf _
338 * @since 4.0.0
339 * @category Lang
340 * @param {*} value The value to process.
341 * @returns {number} Returns the number.
342 * @example
343 *
344 * _.toNumber(3.2);
345 * // => 3.2
346 *
347 * _.toNumber(Number.MIN_VALUE);
348 * // => 5e-324
349 *
350 * _.toNumber(Infinity);
351 * // => Infinity
352 *
353 * _.toNumber('3.2');
354 * // => 3.2
355 */
356function toNumber(value) {
357 if (typeof value == 'number') {
358 return value;
359 }
360 if (isSymbol(value)) {
361 return NAN;
362 }
363 if (isObject(value)) {
364 var other = typeof value.valueOf == 'function' ? value.valueOf() : value;
365 value = isObject(other) ? (other + '') : other;
366 }
367 if (typeof value != 'string') {
368 return value === 0 ? value : +value;
369 }
370 value = value.replace(reTrim, '');
371 var isBinary = reIsBinary.test(value);
372 return (isBinary || reIsOctal.test(value))
373 ? freeParseInt(value.slice(2), isBinary ? 2 : 8)
374 : (reIsBadHex.test(value) ? NAN : +value);
375}
376
377module.exports = debounce;
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