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1// Underscore.js 1.4.4
2// http://underscorejs.org
3// (c) 2009-2013 Jeremy Ashkenas, DocumentCloud Inc.
4// Underscore may be freely distributed under the MIT license.
5
6(function() {
7
8 // Baseline setup
9 // --------------
10
11 // Establish the root object, `window` in the browser, or `global` on the server.
12 var root = this;
13
14 // Save the previous value of the `_` variable.
15 var previousUnderscore = root._;
16
17 // Establish the object that gets returned to break out of a loop iteration.
18 var breaker = {};
19
20 // Save bytes in the minified (but not gzipped) version:
21 var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;
22
23 // Create quick reference variables for speed access to core prototypes.
24 var push = ArrayProto.push,
25 slice = ArrayProto.slice,
26 concat = ArrayProto.concat,
27 toString = ObjProto.toString,
28 hasOwnProperty = ObjProto.hasOwnProperty;
29
30 // All **ECMAScript 5** native function implementations that we hope to use
31 // are declared here.
32 var
33 nativeForEach = ArrayProto.forEach,
34 nativeMap = ArrayProto.map,
35 nativeReduce = ArrayProto.reduce,
36 nativeReduceRight = ArrayProto.reduceRight,
37 nativeFilter = ArrayProto.filter,
38 nativeEvery = ArrayProto.every,
39 nativeSome = ArrayProto.some,
40 nativeIndexOf = ArrayProto.indexOf,
41 nativeLastIndexOf = ArrayProto.lastIndexOf,
42 nativeIsArray = Array.isArray,
43 nativeKeys = Object.keys,
44 nativeBind = FuncProto.bind;
45
46 // Create a safe reference to the Underscore object for use below.
47 var _ = function(obj) {
48 if (obj instanceof _) return obj;
49 if (!(this instanceof _)) return new _(obj);
50 this._wrapped = obj;
51 };
52
53 // Export the Underscore object for **Node.js**, with
54 // backwards-compatibility for the old `require()` API. If we're in
55 // the browser, add `_` as a global object via a string identifier,
56 // for Closure Compiler "advanced" mode.
57 if (typeof exports !== 'undefined') {
58 if (typeof module !== 'undefined' && module.exports) {
59 exports = module.exports = _;
60 }
61 exports._ = _;
62 } else {
63 root._ = _;
64 }
65
66 // Current version.
67 _.VERSION = '1.4.4';
68
69 // Collection Functions
70 // --------------------
71
72 // The cornerstone, an `each` implementation, aka `forEach`.
73 // Handles objects with the built-in `forEach`, arrays, and raw objects.
74 // Delegates to **ECMAScript 5**'s native `forEach` if available.
75 var each = _.each = _.forEach = function(obj, iterator, context) {
76 if (obj == null) return;
77 if (nativeForEach && obj.forEach === nativeForEach) {
78 obj.forEach(iterator, context);
79 } else if (obj.length === +obj.length) {
80 for (var i = 0, l = obj.length; i < l; i++) {
81 if (iterator.call(context, obj[i], i, obj) === breaker) return;
82 }
83 } else {
84 for (var key in obj) {
85 if (_.has(obj, key)) {
86 if (iterator.call(context, obj[key], key, obj) === breaker) return;
87 }
88 }
89 }
90 };
91
92 // Return the results of applying the iterator to each element.
93 // Delegates to **ECMAScript 5**'s native `map` if available.
94 _.map = _.collect = function(obj, iterator, context) {
95 var results = [];
96 if (obj == null) return results;
97 if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
98 each(obj, function(value, index, list) {
99 results[results.length] = iterator.call(context, value, index, list);
100 });
101 return results;
102 };
103
104 var reduceError = 'Reduce of empty array with no initial value';
105
106 // **Reduce** builds up a single result from a list of values, aka `inject`,
107 // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
108 _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
109 var initial = arguments.length > 2;
110 if (obj == null) obj = [];
111 if (nativeReduce && obj.reduce === nativeReduce) {
112 if (context) iterator = _.bind(iterator, context);
113 return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
114 }
115 each(obj, function(value, index, list) {
116 if (!initial) {
117 memo = value;
118 initial = true;
119 } else {
120 memo = iterator.call(context, memo, value, index, list);
121 }
122 });
123 if (!initial) throw new TypeError(reduceError);
124 return memo;
125 };
126
127 // The right-associative version of reduce, also known as `foldr`.
128 // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
129 _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
130 var initial = arguments.length > 2;
131 if (obj == null) obj = [];
132 if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
133 if (context) iterator = _.bind(iterator, context);
134 return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
135 }
136 var length = obj.length;
137 if (length !== +length) {
138 var keys = _.keys(obj);
139 length = keys.length;
140 }
141 each(obj, function(value, index, list) {
142 index = keys ? keys[--length] : --length;
143 if (!initial) {
144 memo = obj[index];
145 initial = true;
146 } else {
147 memo = iterator.call(context, memo, obj[index], index, list);
148 }
149 });
150 if (!initial) throw new TypeError(reduceError);
151 return memo;
152 };
153
154 // Return the first value which passes a truth test. Aliased as `detect`.
155 _.find = _.detect = function(obj, iterator, context) {
156 var result;
157 any(obj, function(value, index, list) {
158 if (iterator.call(context, value, index, list)) {
159 result = value;
160 return true;
161 }
162 });
163 return result;
164 };
165
166 // Return all the elements that pass a truth test.
167 // Delegates to **ECMAScript 5**'s native `filter` if available.
168 // Aliased as `select`.
169 _.filter = _.select = function(obj, iterator, context) {
170 var results = [];
171 if (obj == null) return results;
172 if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
173 each(obj, function(value, index, list) {
174 if (iterator.call(context, value, index, list)) results[results.length] = value;
175 });
176 return results;
177 };
178
179 // Return all the elements for which a truth test fails.
180 _.reject = function(obj, iterator, context) {
181 return _.filter(obj, function(value, index, list) {
182 return !iterator.call(context, value, index, list);
183 }, context);
184 };
185
186 // Determine whether all of the elements match a truth test.
187 // Delegates to **ECMAScript 5**'s native `every` if available.
188 // Aliased as `all`.
189 _.every = _.all = function(obj, iterator, context) {
190 iterator || (iterator = _.identity);
191 var result = true;
192 if (obj == null) return result;
193 if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
194 each(obj, function(value, index, list) {
195 if (!(result = result && iterator.call(context, value, index, list))) return breaker;
196 });
197 return !!result;
198 };
199
200 // Determine if at least one element in the object matches a truth test.
201 // Delegates to **ECMAScript 5**'s native `some` if available.
202 // Aliased as `any`.
203 var any = _.some = _.any = function(obj, iterator, context) {
204 iterator || (iterator = _.identity);
205 var result = false;
206 if (obj == null) return result;
207 if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
208 each(obj, function(value, index, list) {
209 if (result || (result = iterator.call(context, value, index, list))) return breaker;
210 });
211 return !!result;
212 };
213
214 // Determine if the array or object contains a given value (using `===`).
215 // Aliased as `include`.
216 _.contains = _.include = function(obj, target) {
217 if (obj == null) return false;
218 if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
219 return any(obj, function(value) {
220 return value === target;
221 });
222 };
223
224 // Invoke a method (with arguments) on every item in a collection.
225 _.invoke = function(obj, method) {
226 var args = slice.call(arguments, 2);
227 var isFunc = _.isFunction(method);
228 return _.map(obj, function(value) {
229 return (isFunc ? method : value[method]).apply(value, args);
230 });
231 };
232
233 // Convenience version of a common use case of `map`: fetching a property.
234 _.pluck = function(obj, key) {
235 return _.map(obj, function(value){ return value[key]; });
236 };
237
238 // Convenience version of a common use case of `filter`: selecting only objects
239 // containing specific `key:value` pairs.
240 _.where = function(obj, attrs, first) {
241 if (_.isEmpty(attrs)) return first ? null : [];
242 return _[first ? 'find' : 'filter'](obj, function(value) {
243 for (var key in attrs) {
244 if (attrs[key] !== value[key]) return false;
245 }
246 return true;
247 });
248 };
249
250 // Convenience version of a common use case of `find`: getting the first object
251 // containing specific `key:value` pairs.
252 _.findWhere = function(obj, attrs) {
253 return _.where(obj, attrs, true);
254 };
255
256 // Return the maximum element or (element-based computation).
257 // Can't optimize arrays of integers longer than 65,535 elements.
258 // See: https://bugs.webkit.org/show_bug.cgi?id=80797
259 _.max = function(obj, iterator, context) {
260 if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
261 return Math.max.apply(Math, obj);
262 }
263 if (!iterator && _.isEmpty(obj)) return -Infinity;
264 var result = {computed : -Infinity, value: -Infinity};
265 each(obj, function(value, index, list) {
266 var computed = iterator ? iterator.call(context, value, index, list) : value;
267 computed >= result.computed && (result = {value : value, computed : computed});
268 });
269 return result.value;
270 };
271
272 // Return the minimum element (or element-based computation).
273 _.min = function(obj, iterator, context) {
274 if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
275 return Math.min.apply(Math, obj);
276 }
277 if (!iterator && _.isEmpty(obj)) return Infinity;
278 var result = {computed : Infinity, value: Infinity};
279 each(obj, function(value, index, list) {
280 var computed = iterator ? iterator.call(context, value, index, list) : value;
281 computed < result.computed && (result = {value : value, computed : computed});
282 });
283 return result.value;
284 };
285
286 // Shuffle an array.
287 _.shuffle = function(obj) {
288 var rand;
289 var index = 0;
290 var shuffled = [];
291 each(obj, function(value) {
292 rand = _.random(index++);
293 shuffled[index - 1] = shuffled[rand];
294 shuffled[rand] = value;
295 });
296 return shuffled;
297 };
298
299 // An internal function to generate lookup iterators.
300 var lookupIterator = function(value) {
301 return _.isFunction(value) ? value : function(obj){ return obj[value]; };
302 };
303
304 // Sort the object's values by a criterion produced by an iterator.
305 _.sortBy = function(obj, value, context) {
306 var iterator = lookupIterator(value);
307 return _.pluck(_.map(obj, function(value, index, list) {
308 return {
309 value : value,
310 index : index,
311 criteria : iterator.call(context, value, index, list)
312 };
313 }).sort(function(left, right) {
314 var a = left.criteria;
315 var b = right.criteria;
316 if (a !== b) {
317 if (a > b || a === void 0) return 1;
318 if (a < b || b === void 0) return -1;
319 }
320 return left.index < right.index ? -1 : 1;
321 }), 'value');
322 };
323
324 // An internal function used for aggregate "group by" operations.
325 var group = function(obj, value, context, behavior) {
326 var result = {};
327 var iterator = lookupIterator(value || _.identity);
328 each(obj, function(value, index) {
329 var key = iterator.call(context, value, index, obj);
330 behavior(result, key, value);
331 });
332 return result;
333 };
334
335 // Groups the object's values by a criterion. Pass either a string attribute
336 // to group by, or a function that returns the criterion.
337 _.groupBy = function(obj, value, context) {
338 return group(obj, value, context, function(result, key, value) {
339 (_.has(result, key) ? result[key] : (result[key] = [])).push(value);
340 });
341 };
342
343 // Counts instances of an object that group by a certain criterion. Pass
344 // either a string attribute to count by, or a function that returns the
345 // criterion.
346 _.countBy = function(obj, value, context) {
347 return group(obj, value, context, function(result, key) {
348 if (!_.has(result, key)) result[key] = 0;
349 result[key]++;
350 });
351 };
352
353 // Use a comparator function to figure out the smallest index at which
354 // an object should be inserted so as to maintain order. Uses binary search.
355 _.sortedIndex = function(array, obj, iterator, context) {
356 iterator = iterator == null ? _.identity : lookupIterator(iterator);
357 var value = iterator.call(context, obj);
358 var low = 0, high = array.length;
359 while (low < high) {
360 var mid = (low + high) >>> 1;
361 iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid;
362 }
363 return low;
364 };
365
366 // Safely convert anything iterable into a real, live array.
367 _.toArray = function(obj) {
368 if (!obj) return [];
369 if (_.isArray(obj)) return slice.call(obj);
370 if (obj.length === +obj.length) return _.map(obj, _.identity);
371 return _.values(obj);
372 };
373
374 // Return the number of elements in an object.
375 _.size = function(obj) {
376 if (obj == null) return 0;
377 return (obj.length === +obj.length) ? obj.length : _.keys(obj).length;
378 };
379
380 // Array Functions
381 // ---------------
382
383 // Get the first element of an array. Passing **n** will return the first N
384 // values in the array. Aliased as `head` and `take`. The **guard** check
385 // allows it to work with `_.map`.
386 _.first = _.head = _.take = function(array, n, guard) {
387 if (array == null) return void 0;
388 return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
389 };
390
391 // Returns everything but the last entry of the array. Especially useful on
392 // the arguments object. Passing **n** will return all the values in
393 // the array, excluding the last N. The **guard** check allows it to work with
394 // `_.map`.
395 _.initial = function(array, n, guard) {
396 return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
397 };
398
399 // Get the last element of an array. Passing **n** will return the last N
400 // values in the array. The **guard** check allows it to work with `_.map`.
401 _.last = function(array, n, guard) {
402 if (array == null) return void 0;
403 if ((n != null) && !guard) {
404 return slice.call(array, Math.max(array.length - n, 0));
405 } else {
406 return array[array.length - 1];
407 }
408 };
409
410 // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
411 // Especially useful on the arguments object. Passing an **n** will return
412 // the rest N values in the array. The **guard**
413 // check allows it to work with `_.map`.
414 _.rest = _.tail = _.drop = function(array, n, guard) {
415 return slice.call(array, (n == null) || guard ? 1 : n);
416 };
417
418 // Trim out all falsy values from an array.
419 _.compact = function(array) {
420 return _.filter(array, _.identity);
421 };
422
423 // Internal implementation of a recursive `flatten` function.
424 var flatten = function(input, shallow, output) {
425 each(input, function(value) {
426 if (_.isArray(value)) {
427 shallow ? push.apply(output, value) : flatten(value, shallow, output);
428 } else {
429 output.push(value);
430 }
431 });
432 return output;
433 };
434
435 // Return a completely flattened version of an array.
436 _.flatten = function(array, shallow) {
437 return flatten(array, shallow, []);
438 };
439
440 // Return a version of the array that does not contain the specified value(s).
441 _.without = function(array) {
442 return _.difference(array, slice.call(arguments, 1));
443 };
444
445 // Produce a duplicate-free version of the array. If the array has already
446 // been sorted, you have the option of using a faster algorithm.
447 // Aliased as `unique`.
448 _.uniq = _.unique = function(array, isSorted, iterator, context) {
449 if (_.isFunction(isSorted)) {
450 context = iterator;
451 iterator = isSorted;
452 isSorted = false;
453 }
454 var initial = iterator ? _.map(array, iterator, context) : array;
455 var results = [];
456 var seen = [];
457 each(initial, function(value, index) {
458 if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) {
459 seen.push(value);
460 results.push(array[index]);
461 }
462 });
463 return results;
464 };
465
466 // Produce an array that contains the union: each distinct element from all of
467 // the passed-in arrays.
468 _.union = function() {
469 return _.uniq(concat.apply(ArrayProto, arguments));
470 };
471
472 // Produce an array that contains every item shared between all the
473 // passed-in arrays.
474 _.intersection = function(array) {
475 var rest = slice.call(arguments, 1);
476 return _.filter(_.uniq(array), function(item) {
477 return _.every(rest, function(other) {
478 return _.indexOf(other, item) >= 0;
479 });
480 });
481 };
482
483 // Take the difference between one array and a number of other arrays.
484 // Only the elements present in just the first array will remain.
485 _.difference = function(array) {
486 var rest = concat.apply(ArrayProto, slice.call(arguments, 1));
487 return _.filter(array, function(value){ return !_.contains(rest, value); });
488 };
489
490 // Zip together multiple lists into a single array -- elements that share
491 // an index go together.
492 _.zip = function() {
493 var args = slice.call(arguments);
494 var length = _.max(_.pluck(args, 'length'));
495 var results = new Array(length);
496 for (var i = 0; i < length; i++) {
497 results[i] = _.pluck(args, "" + i);
498 }
499 return results;
500 };
501
502 // Converts lists into objects. Pass either a single array of `[key, value]`
503 // pairs, or two parallel arrays of the same length -- one of keys, and one of
504 // the corresponding values.
505 _.object = function(list, values) {
506 if (list == null) return {};
507 var result = {};
508 for (var i = 0, l = list.length; i < l; i++) {
509 if (values) {
510 result[list[i]] = values[i];
511 } else {
512 result[list[i][0]] = list[i][1];
513 }
514 }
515 return result;
516 };
517
518 // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
519 // we need this function. Return the position of the first occurrence of an
520 // item in an array, or -1 if the item is not included in the array.
521 // Delegates to **ECMAScript 5**'s native `indexOf` if available.
522 // If the array is large and already in sort order, pass `true`
523 // for **isSorted** to use binary search.
524 _.indexOf = function(array, item, isSorted) {
525 if (array == null) return -1;
526 var i = 0, l = array.length;
527 if (isSorted) {
528 if (typeof isSorted == 'number') {
529 i = (isSorted < 0 ? Math.max(0, l + isSorted) : isSorted);
530 } else {
531 i = _.sortedIndex(array, item);
532 return array[i] === item ? i : -1;
533 }
534 }
535 if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted);
536 for (; i < l; i++) if (array[i] === item) return i;
537 return -1;
538 };
539
540 // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
541 _.lastIndexOf = function(array, item, from) {
542 if (array == null) return -1;
543 var hasIndex = from != null;
544 if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) {
545 return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item);
546 }
547 var i = (hasIndex ? from : array.length);
548 while (i--) if (array[i] === item) return i;
549 return -1;
550 };
551
552 // Generate an integer Array containing an arithmetic progression. A port of
553 // the native Python `range()` function. See
554 // [the Python documentation](http://docs.python.org/library/functions.html#range).
555 _.range = function(start, stop, step) {
556 if (arguments.length <= 1) {
557 stop = start || 0;
558 start = 0;
559 }
560 step = arguments[2] || 1;
561
562 var len = Math.max(Math.ceil((stop - start) / step), 0);
563 var idx = 0;
564 var range = new Array(len);
565
566 while(idx < len) {
567 range[idx++] = start;
568 start += step;
569 }
570
571 return range;
572 };
573
574 // Function (ahem) Functions
575 // ------------------
576
577 // Create a function bound to a given object (assigning `this`, and arguments,
578 // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
579 // available.
580 _.bind = function(func, context) {
581 if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
582 var args = slice.call(arguments, 2);
583 return function() {
584 return func.apply(context, args.concat(slice.call(arguments)));
585 };
586 };
587
588 // Partially apply a function by creating a version that has had some of its
589 // arguments pre-filled, without changing its dynamic `this` context.
590 _.partial = function(func) {
591 var args = slice.call(arguments, 1);
592 return function() {
593 return func.apply(this, args.concat(slice.call(arguments)));
594 };
595 };
596
597 // Bind all of an object's methods to that object. Useful for ensuring that
598 // all callbacks defined on an object belong to it.
599 _.bindAll = function(obj) {
600 var funcs = slice.call(arguments, 1);
601 if (funcs.length === 0) funcs = _.functions(obj);
602 each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
603 return obj;
604 };
605
606 // Memoize an expensive function by storing its results.
607 _.memoize = function(func, hasher) {
608 var memo = {};
609 hasher || (hasher = _.identity);
610 return function() {
611 var key = hasher.apply(this, arguments);
612 return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
613 };
614 };
615
616 // Delays a function for the given number of milliseconds, and then calls
617 // it with the arguments supplied.
618 _.delay = function(func, wait) {
619 var args = slice.call(arguments, 2);
620 return setTimeout(function(){ return func.apply(null, args); }, wait);
621 };
622
623 // Defers a function, scheduling it to run after the current call stack has
624 // cleared.
625 _.defer = function(func) {
626 return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
627 };
628
629 // Returns a function, that, when invoked, will only be triggered at most once
630 // during a given window of time.
631 _.throttle = function(func, wait) {
632 var context, args, timeout, result;
633 var previous = 0;
634 var later = function() {
635 previous = new Date;
636 timeout = null;
637 result = func.apply(context, args);
638 };
639 return function() {
640 var now = new Date;
641 var remaining = wait - (now - previous);
642 context = this;
643 args = arguments;
644 if (remaining <= 0) {
645 clearTimeout(timeout);
646 timeout = null;
647 previous = now;
648 result = func.apply(context, args);
649 } else if (!timeout) {
650 timeout = setTimeout(later, remaining);
651 }
652 return result;
653 };
654 };
655
656 // Returns a function, that, as long as it continues to be invoked, will not
657 // be triggered. The function will be called after it stops being called for
658 // N milliseconds. If `immediate` is passed, trigger the function on the
659 // leading edge, instead of the trailing.
660 _.debounce = function(func, wait, immediate) {
661 var timeout, result;
662 return function() {
663 var context = this, args = arguments;
664 var later = function() {
665 timeout = null;
666 if (!immediate) result = func.apply(context, args);
667 };
668 var callNow = immediate && !timeout;
669 clearTimeout(timeout);
670 timeout = setTimeout(later, wait);
671 if (callNow) result = func.apply(context, args);
672 return result;
673 };
674 };
675
676 // Returns a function that will be executed at most one time, no matter how
677 // often you call it. Useful for lazy initialization.
678 _.once = function(func) {
679 var ran = false, memo;
680 return function() {
681 if (ran) return memo;
682 ran = true;
683 memo = func.apply(this, arguments);
684 func = null;
685 return memo;
686 };
687 };
688
689 // Returns the first function passed as an argument to the second,
690 // allowing you to adjust arguments, run code before and after, and
691 // conditionally execute the original function.
692 _.wrap = function(func, wrapper) {
693 return function() {
694 var args = [func];
695 push.apply(args, arguments);
696 return wrapper.apply(this, args);
697 };
698 };
699
700 // Returns a function that is the composition of a list of functions, each
701 // consuming the return value of the function that follows.
702 _.compose = function() {
703 var funcs = arguments;
704 return function() {
705 var args = arguments;
706 for (var i = funcs.length - 1; i >= 0; i--) {
707 args = [funcs[i].apply(this, args)];
708 }
709 return args[0];
710 };
711 };
712
713 // Returns a function that will only be executed after being called N times.
714 _.after = function(times, func) {
715 if (times <= 0) return func();
716 return function() {
717 if (--times < 1) {
718 return func.apply(this, arguments);
719 }
720 };
721 };
722
723 // Object Functions
724 // ----------------
725
726 // Retrieve the names of an object's properties.
727 // Delegates to **ECMAScript 5**'s native `Object.keys`
728 _.keys = nativeKeys || function(obj) {
729 if (obj !== Object(obj)) throw new TypeError('Invalid object');
730 var keys = [];
731 for (var key in obj) if (_.has(obj, key)) keys[keys.length] = key;
732 return keys;
733 };
734
735 // Retrieve the values of an object's properties.
736 _.values = function(obj) {
737 var values = [];
738 for (var key in obj) if (_.has(obj, key)) values.push(obj[key]);
739 return values;
740 };
741
742 // Convert an object into a list of `[key, value]` pairs.
743 _.pairs = function(obj) {
744 var pairs = [];
745 for (var key in obj) if (_.has(obj, key)) pairs.push([key, obj[key]]);
746 return pairs;
747 };
748
749 // Invert the keys and values of an object. The values must be serializable.
750 _.invert = function(obj) {
751 var result = {};
752 for (var key in obj) if (_.has(obj, key)) result[obj[key]] = key;
753 return result;
754 };
755
756 // Return a sorted list of the function names available on the object.
757 // Aliased as `methods`
758 _.functions = _.methods = function(obj) {
759 var names = [];
760 for (var key in obj) {
761 if (_.isFunction(obj[key])) names.push(key);
762 }
763 return names.sort();
764 };
765
766 // Extend a given object with all the properties in passed-in object(s).
767 _.extend = function(obj) {
768 each(slice.call(arguments, 1), function(source) {
769 if (source) {
770 for (var prop in source) {
771 obj[prop] = source[prop];
772 }
773 }
774 });
775 return obj;
776 };
777
778 // Return a copy of the object only containing the whitelisted properties.
779 _.pick = function(obj) {
780 var copy = {};
781 var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
782 each(keys, function(key) {
783 if (key in obj) copy[key] = obj[key];
784 });
785 return copy;
786 };
787
788 // Return a copy of the object without the blacklisted properties.
789 _.omit = function(obj) {
790 var copy = {};
791 var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
792 for (var key in obj) {
793 if (!_.contains(keys, key)) copy[key] = obj[key];
794 }
795 return copy;
796 };
797
798 // Fill in a given object with default properties.
799 _.defaults = function(obj) {
800 each(slice.call(arguments, 1), function(source) {
801 if (source) {
802 for (var prop in source) {
803 if (obj[prop] == null) obj[prop] = source[prop];
804 }
805 }
806 });
807 return obj;
808 };
809
810 // Create a (shallow-cloned) duplicate of an object.
811 _.clone = function(obj) {
812 if (!_.isObject(obj)) return obj;
813 return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
814 };
815
816 // Invokes interceptor with the obj, and then returns obj.
817 // The primary purpose of this method is to "tap into" a method chain, in
818 // order to perform operations on intermediate results within the chain.
819 _.tap = function(obj, interceptor) {
820 interceptor(obj);
821 return obj;
822 };
823
824 // Internal recursive comparison function for `isEqual`.
825 var eq = function(a, b, aStack, bStack) {
826 // Identical objects are equal. `0 === -0`, but they aren't identical.
827 // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
828 if (a === b) return a !== 0 || 1 / a == 1 / b;
829 // A strict comparison is necessary because `null == undefined`.
830 if (a == null || b == null) return a === b;
831 // Unwrap any wrapped objects.
832 if (a instanceof _) a = a._wrapped;
833 if (b instanceof _) b = b._wrapped;
834 // Compare `[[Class]]` names.
835 var className = toString.call(a);
836 if (className != toString.call(b)) return false;
837 switch (className) {
838 // Strings, numbers, dates, and booleans are compared by value.
839 case '[object String]':
840 // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
841 // equivalent to `new String("5")`.
842 return a == String(b);
843 case '[object Number]':
844 // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
845 // other numeric values.
846 return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
847 case '[object Date]':
848 case '[object Boolean]':
849 // Coerce dates and booleans to numeric primitive values. Dates are compared by their
850 // millisecond representations. Note that invalid dates with millisecond representations
851 // of `NaN` are not equivalent.
852 return +a == +b;
853 // RegExps are compared by their source patterns and flags.
854 case '[object RegExp]':
855 return a.source == b.source &&
856 a.global == b.global &&
857 a.multiline == b.multiline &&
858 a.ignoreCase == b.ignoreCase;
859 }
860 if (typeof a != 'object' || typeof b != 'object') return false;
861 // Assume equality for cyclic structures. The algorithm for detecting cyclic
862 // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
863 var length = aStack.length;
864 while (length--) {
865 // Linear search. Performance is inversely proportional to the number of
866 // unique nested structures.
867 if (aStack[length] == a) return bStack[length] == b;
868 }
869 // Add the first object to the stack of traversed objects.
870 aStack.push(a);
871 bStack.push(b);
872 var size = 0, result = true;
873 // Recursively compare objects and arrays.
874 if (className == '[object Array]') {
875 // Compare array lengths to determine if a deep comparison is necessary.
876 size = a.length;
877 result = size == b.length;
878 if (result) {
879 // Deep compare the contents, ignoring non-numeric properties.
880 while (size--) {
881 if (!(result = eq(a[size], b[size], aStack, bStack))) break;
882 }
883 }
884 } else {
885 // Objects with different constructors are not equivalent, but `Object`s
886 // from different frames are.
887 var aCtor = a.constructor, bCtor = b.constructor;
888 if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
889 _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
890 return false;
891 }
892 // Deep compare objects.
893 for (var key in a) {
894 if (_.has(a, key)) {
895 // Count the expected number of properties.
896 size++;
897 // Deep compare each member.
898 if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break;
899 }
900 }
901 // Ensure that both objects contain the same number of properties.
902 if (result) {
903 for (key in b) {
904 if (_.has(b, key) && !(size--)) break;
905 }
906 result = !size;
907 }
908 }
909 // Remove the first object from the stack of traversed objects.
910 aStack.pop();
911 bStack.pop();
912 return result;
913 };
914
915 // Perform a deep comparison to check if two objects are equal.
916 _.isEqual = function(a, b) {
917 return eq(a, b, [], []);
918 };
919
920 // Is a given array, string, or object empty?
921 // An "empty" object has no enumerable own-properties.
922 _.isEmpty = function(obj) {
923 if (obj == null) return true;
924 if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
925 for (var key in obj) if (_.has(obj, key)) return false;
926 return true;
927 };
928
929 // Is a given value a DOM element?
930 _.isElement = function(obj) {
931 return !!(obj && obj.nodeType === 1);
932 };
933
934 // Is a given value an array?
935 // Delegates to ECMA5's native Array.isArray
936 _.isArray = nativeIsArray || function(obj) {
937 return toString.call(obj) == '[object Array]';
938 };
939
940 // Is a given variable an object?
941 _.isObject = function(obj) {
942 return obj === Object(obj);
943 };
944
945 // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp.
946 each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) {
947 _['is' + name] = function(obj) {
948 return toString.call(obj) == '[object ' + name + ']';
949 };
950 });
951
952 // Define a fallback version of the method in browsers (ahem, IE), where
953 // there isn't any inspectable "Arguments" type.
954 if (!_.isArguments(arguments)) {
955 _.isArguments = function(obj) {
956 return !!(obj && _.has(obj, 'callee'));
957 };
958 }
959
960 // Optimize `isFunction` if appropriate.
961 if (typeof (/./) !== 'function') {
962 _.isFunction = function(obj) {
963 return typeof obj === 'function';
964 };
965 }
966
967 // Is a given object a finite number?
968 _.isFinite = function(obj) {
969 return isFinite(obj) && !isNaN(parseFloat(obj));
970 };
971
972 // Is the given value `NaN`? (NaN is the only number which does not equal itself).
973 _.isNaN = function(obj) {
974 return _.isNumber(obj) && obj != +obj;
975 };
976
977 // Is a given value a boolean?
978 _.isBoolean = function(obj) {
979 return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
980 };
981
982 // Is a given value equal to null?
983 _.isNull = function(obj) {
984 return obj === null;
985 };
986
987 // Is a given variable undefined?
988 _.isUndefined = function(obj) {
989 return obj === void 0;
990 };
991
992 // Shortcut function for checking if an object has a given property directly
993 // on itself (in other words, not on a prototype).
994 _.has = function(obj, key) {
995 return hasOwnProperty.call(obj, key);
996 };
997
998 // Utility Functions
999 // -----------------
1000
1001 // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
1002 // previous owner. Returns a reference to the Underscore object.
1003 _.noConflict = function() {
1004 root._ = previousUnderscore;
1005 return this;
1006 };
1007
1008 // Keep the identity function around for default iterators.
1009 _.identity = function(value) {
1010 return value;
1011 };
1012
1013 // Run a function **n** times.
1014 _.times = function(n, iterator, context) {
1015 var accum = Array(n);
1016 for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i);
1017 return accum;
1018 };
1019
1020 // Return a random integer between min and max (inclusive).
1021 _.random = function(min, max) {
1022 if (max == null) {
1023 max = min;
1024 min = 0;
1025 }
1026 return min + Math.floor(Math.random() * (max - min + 1));
1027 };
1028
1029 // List of HTML entities for escaping.
1030 var entityMap = {
1031 escape: {
1032 '&': '&amp;',
1033 '<': '&lt;',
1034 '>': '&gt;',
1035 '"': '&quot;',
1036 "'": '&#x27;',
1037 '/': '&#x2F;'
1038 }
1039 };
1040 entityMap.unescape = _.invert(entityMap.escape);
1041
1042 // Regexes containing the keys and values listed immediately above.
1043 var entityRegexes = {
1044 escape: new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'),
1045 unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g')
1046 };
1047
1048 // Functions for escaping and unescaping strings to/from HTML interpolation.
1049 _.each(['escape', 'unescape'], function(method) {
1050 _[method] = function(string) {
1051 if (string == null) return '';
1052 return ('' + string).replace(entityRegexes[method], function(match) {
1053 return entityMap[method][match];
1054 });
1055 };
1056 });
1057
1058 // If the value of the named property is a function then invoke it;
1059 // otherwise, return it.
1060 _.result = function(object, property) {
1061 if (object == null) return null;
1062 var value = object[property];
1063 return _.isFunction(value) ? value.call(object) : value;
1064 };
1065
1066 // Add your own custom functions to the Underscore object.
1067 _.mixin = function(obj) {
1068 each(_.functions(obj), function(name){
1069 var func = _[name] = obj[name];
1070 _.prototype[name] = function() {
1071 var args = [this._wrapped];
1072 push.apply(args, arguments);
1073 return result.call(this, func.apply(_, args));
1074 };
1075 });
1076 };
1077
1078 // Generate a unique integer id (unique within the entire client session).
1079 // Useful for temporary DOM ids.
1080 var idCounter = 0;
1081 _.uniqueId = function(prefix) {
1082 var id = ++idCounter + '';
1083 return prefix ? prefix + id : id;
1084 };
1085
1086 // By default, Underscore uses ERB-style template delimiters, change the
1087 // following template settings to use alternative delimiters.
1088 _.templateSettings = {
1089 evaluate : /<%([\s\S]+?)%>/g,
1090 interpolate : /<%=([\s\S]+?)%>/g,
1091 escape : /<%-([\s\S]+?)%>/g
1092 };
1093
1094 // When customizing `templateSettings`, if you don't want to define an
1095 // interpolation, evaluation or escaping regex, we need one that is
1096 // guaranteed not to match.
1097 var noMatch = /(.)^/;
1098
1099 // Certain characters need to be escaped so that they can be put into a
1100 // string literal.
1101 var escapes = {
1102 "'": "'",
1103 '\\': '\\',
1104 '\r': 'r',
1105 '\n': 'n',
1106 '\t': 't',
1107 '\u2028': 'u2028',
1108 '\u2029': 'u2029'
1109 };
1110
1111 var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;
1112
1113 // JavaScript micro-templating, similar to John Resig's implementation.
1114 // Underscore templating handles arbitrary delimiters, preserves whitespace,
1115 // and correctly escapes quotes within interpolated code.
1116 _.template = function(text, data, settings) {
1117 var render;
1118 settings = _.defaults({}, settings, _.templateSettings);
1119
1120 // Combine delimiters into one regular expression via alternation.
1121 var matcher = new RegExp([
1122 (settings.escape || noMatch).source,
1123 (settings.interpolate || noMatch).source,
1124 (settings.evaluate || noMatch).source
1125 ].join('|') + '|$', 'g');
1126
1127 // Compile the template source, escaping string literals appropriately.
1128 var index = 0;
1129 var source = "__p+='";
1130 text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
1131 source += text.slice(index, offset)
1132 .replace(escaper, function(match) { return '\\' + escapes[match]; });
1133
1134 if (escape) {
1135 source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
1136 }
1137 if (interpolate) {
1138 source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
1139 }
1140 if (evaluate) {
1141 source += "';\n" + evaluate + "\n__p+='";
1142 }
1143 index = offset + match.length;
1144 return match;
1145 });
1146 source += "';\n";
1147
1148 // If a variable is not specified, place data values in local scope.
1149 if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
1150
1151 source = "var __t,__p='',__j=Array.prototype.join," +
1152 "print=function(){__p+=__j.call(arguments,'');};\n" +
1153 source + "return __p;\n";
1154
1155 try {
1156 render = new Function(settings.variable || 'obj', '_', source);
1157 } catch (e) {
1158 e.source = source;
1159 throw e;
1160 }
1161
1162 if (data) return render(data, _);
1163 var template = function(data) {
1164 return render.call(this, data, _);
1165 };
1166
1167 // Provide the compiled function source as a convenience for precompilation.
1168 template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';
1169
1170 return template;
1171 };
1172
1173 // Add a "chain" function, which will delegate to the wrapper.
1174 _.chain = function(obj) {
1175 return _(obj).chain();
1176 };
1177
1178 // OOP
1179 // ---------------
1180 // If Underscore is called as a function, it returns a wrapped object that
1181 // can be used OO-style. This wrapper holds altered versions of all the
1182 // underscore functions. Wrapped objects may be chained.
1183
1184 // Helper function to continue chaining intermediate results.
1185 var result = function(obj) {
1186 return this._chain ? _(obj).chain() : obj;
1187 };
1188
1189 // Add all of the Underscore functions to the wrapper object.
1190 _.mixin(_);
1191
1192 // Add all mutator Array functions to the wrapper.
1193 each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
1194 var method = ArrayProto[name];
1195 _.prototype[name] = function() {
1196 var obj = this._wrapped;
1197 method.apply(obj, arguments);
1198 if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0];
1199 return result.call(this, obj);
1200 };
1201 });
1202
1203 // Add all accessor Array functions to the wrapper.
1204 each(['concat', 'join', 'slice'], function(name) {
1205 var method = ArrayProto[name];
1206 _.prototype[name] = function() {
1207 return result.call(this, method.apply(this._wrapped, arguments));
1208 };
1209 });
1210
1211 _.extend(_.prototype, {
1212
1213 // Start chaining a wrapped Underscore object.
1214 chain: function() {
1215 this._chain = true;
1216 return this;
1217 },
1218
1219 // Extracts the result from a wrapped and chained object.
1220 value: function() {
1221 return this._wrapped;
1222 }
1223
1224 });
1225
1226}).call(this);