1// Underscore.js 1.6.0 2// http://underscorejs.org 3// (c) 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors 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 `exports` 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 25 push = ArrayProto.push, 26 slice = ArrayProto.slice, 27 concat = ArrayProto.concat, 28 toString = ObjProto.toString, 29 hasOwnProperty = ObjProto.hasOwnProperty; 30 31 // All **ECMAScript 5** native function implementations that we hope to use 32 // are declared here. 33 var 34 nativeForEach = ArrayProto.forEach, 35 nativeMap = ArrayProto.map, 36 nativeReduce = ArrayProto.reduce, 37 nativeReduceRight = ArrayProto.reduceRight, 38 nativeFilter = ArrayProto.filter, 39 nativeEvery = ArrayProto.every, 40 nativeSome = ArrayProto.some, 41 nativeIndexOf = ArrayProto.indexOf, 42 nativeLastIndexOf = ArrayProto.lastIndexOf, 43 nativeIsArray = Array.isArray, 44 nativeKeys = Object.keys, 45 nativeBind = FuncProto.bind; 46 47 // Create a safe reference to the Underscore object for use below. 48 var _ = function(obj) { 49 if (obj instanceof _) return obj; 50 if (!(this instanceof _)) return new _(obj); 51 this._wrapped = obj; 52 }; 53 54 // Export the Underscore object for **Node.js**, with 55 // backwards-compatibility for the old `require()` API. If we're in 56 // the browser, add `_` as a global object via a string identifier, 57 // for Closure Compiler "advanced" mode. 58 if (typeof exports !== 'undefined') { 59 if (typeof module !== 'undefined' && module.exports) { 60 exports = module.exports = _; 61 } 62 exports._ = _; 63 } else { 64 root._ = _; 65 } 66 67 // Current version. 68 _.VERSION = '1.6.0'; 69 70 // Collection Functions 71 // -------------------- 72 73 // The cornerstone, an `each` implementation, aka `forEach`. 74 // Handles objects with the built-in `forEach`, arrays, and raw objects. 75 // Delegates to **ECMAScript 5**'s native `forEach` if available. 76 var each = _.each = _.forEach = function(obj, iterator, context) { 77 if (obj == null) return obj; 78 if (nativeForEach && obj.forEach === nativeForEach) { 79 obj.forEach(iterator, context); 80 } else if (obj.length === +obj.length) { 81 for (var i = 0, length = obj.length; i < length; i++) { 82 if (iterator.call(context, obj[i], i, obj) === breaker) return; 83 } 84 } else { 85 var keys = _.keys(obj); 86 for (var i = 0, length = keys.length; i < length; i++) { 87 if (iterator.call(context, obj[keys[i]], keys[i], obj) === breaker) return; 88 } 89 } 90 return obj; 91 }; 92 93 // Return the results of applying the iterator to each element. 94 // Delegates to **ECMAScript 5**'s native `map` if available. 95 _.map = _.collect = function(obj, iterator, context) { 96 var results = []; 97 if (obj == null) return results; 98 if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context); 99 each(obj, function(value, index, list) { 100 results.push(iterator.call(context, value, index, list)); 101 }); 102 return results; 103 }; 104 105 var reduceError = 'Reduce of empty array with no initial value'; 106 107 // **Reduce** builds up a single result from a list of values, aka `inject`, 108 // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available. 109 _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) { 110 var initial = arguments.length > 2; 111 if (obj == null) obj = []; 112 if (nativeReduce && obj.reduce === nativeReduce) { 113 if (context) iterator = _.bind(iterator, context); 114 return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator); 115 } 116 each(obj, function(value, index, list) { 117 if (!initial) { 118 memo = value; 119 initial = true; 120 } else { 121 memo = iterator.call(context, memo, value, index, list); 122 } 123 }); 124 if (!initial) throw new TypeError(reduceError); 125 return memo; 126 }; 127 128 // The right-associative version of reduce, also known as `foldr`. 129 // Delegates to **ECMAScript 5**'s native `reduceRight` if available. 130 _.reduceRight = _.foldr = function(obj, iterator, memo, context) { 131 var initial = arguments.length > 2; 132 if (obj == null) obj = []; 133 if (nativeReduceRight && obj.reduceRight === nativeReduceRight) { 134 if (context) iterator = _.bind(iterator, context); 135 return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator); 136 } 137 var length = obj.length; 138 if (length !== +length) { 139 var keys = _.keys(obj); 140 length = keys.length; 141 } 142 each(obj, function(value, index, list) { 143 index = keys ? keys[--length] : --length; 144 if (!initial) { 145 memo = obj[index]; 146 initial = true; 147 } else { 148 memo = iterator.call(context, memo, obj[index], index, list); 149 } 150 }); 151 if (!initial) throw new TypeError(reduceError); 152 return memo; 153 }; 154 155 // Return the first value which passes a truth test. Aliased as `detect`. 156 _.find = _.detect = function(obj, predicate, context) { 157 var result; 158 any(obj, function(value, index, list) { 159 if (predicate.call(context, value, index, list)) { 160 result = value; 161 return true; 162 } 163 }); 164 return result; 165 }; 166 167 // Return all the elements that pass a truth test. 168 // Delegates to **ECMAScript 5**'s native `filter` if available. 169 // Aliased as `select`. 170 _.filter = _.select = function(obj, predicate, context) { 171 var results = []; 172 if (obj == null) return results; 173 if (nativeFilter && obj.filter === nativeFilter) return obj.filter(predicate, context); 174 each(obj, function(value, index, list) { 175 if (predicate.call(context, value, index, list)) results.push(value); 176 }); 177 return results; 178 }; 179 180 // Return all the elements for which a truth test fails. 181 _.reject = function(obj, predicate, context) { 182 return _.filter(obj, function(value, index, list) { 183 return !predicate.call(context, value, index, list); 184 }, context); 185 }; 186 187 // Determine whether all of the elements match a truth test. 188 // Delegates to **ECMAScript 5**'s native `every` if available. 189 // Aliased as `all`. 190 _.every = _.all = function(obj, predicate, context) { 191 predicate || (predicate = _.identity); 192 var result = true; 193 if (obj == null) return result; 194 if (nativeEvery && obj.every === nativeEvery) return obj.every(predicate, context); 195 each(obj, function(value, index, list) { 196 if (!(result = result && predicate.call(context, value, index, list))) return breaker; 197 }); 198 return !!result; 199 }; 200 201 // Determine if at least one element in the object matches a truth test. 202 // Delegates to **ECMAScript 5**'s native `some` if available. 203 // Aliased as `any`. 204 var any = _.some = _.any = function(obj, predicate, context) { 205 predicate || (predicate = _.identity); 206 var result = false;
207 if (obj == null) return result; 208 if (nativeSome && obj.some === nativeSome) return obj.some(predicate, context); 209 each(obj, function(value, index, list) { 210 if (result || (result = predicate.call(context, value, index, list))) return breaker; 211 }); 212 return !!result; 213 }; 214 215 // Determine if the array or object contains a given value (using `===`). 216 // Aliased as `include`. 217 _.contains = _.include = function(obj, target) { 218 if (obj == null) return false; 219 if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1; 220 return any(obj, function(value) { 221 return value === target; 222 }); 223 }; 224 225 // Invoke a method (with arguments) on every item in a collection. 226 _.invoke = function(obj, method) { 227 var args = slice.call(arguments, 2); 228 var isFunc = _.isFunction(method); 229 return _.map(obj, function(value) { 230 return (isFunc ? method : value[method]).apply(value, args); 231 }); 232 }; 233 234 // Convenience version of a common use case of `map`: fetching a property. 235 _.pluck = function(obj, key) { 236 return _.map(obj, _.property(key)); 237 }; 238 239 // Convenience version of a common use case of `filter`: selecting only objects 240 // containing specific `key:value` pairs. 241 _.where = function(obj, attrs) { 242 return _.filter(obj, _.matches(attrs)); 243 }; 244 245 // Convenience version of a common use case of `find`: getting the first object 246 // containing specific `key:value` pairs. 247 _.findWhere = function(obj, attrs) { 248 return _.find(obj, _.matches(attrs)); 249 }; 250 251 // Return the maximum element or (element-based computation). 252 // Can't optimize arrays of integers longer than 65,535 elements. 253 // See [WebKit Bug 80797](https://bugs.webkit.org/show_bug.cgi?id=80797) 254 _.max = function(obj, iterator, context) { 255 if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) { 256 return Math.max.apply(Math, obj); 257 } 258 var result = -Infinity, lastComputed = -Infinity; 259 each(obj, function(value, index, list) { 260 var computed = iterator ? iterator.call(context, value, index, list) : value; 261 if (computed > lastComputed) { 262 result = value; 263 lastComputed = computed; 264 } 265 }); 266 return result; 267 }; 268 269 // Return the minimum element (or element-based computation). 270 _.min = function(obj, iterator, context) { 271 if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) { 272 return Math.min.apply(Math, obj); 273 } 274 var result = Infinity, lastComputed = Infinity; 275 each(obj, function(value, index, list) { 276 var computed = iterator ? iterator.call(context, value, index, list) : value; 277 if (computed < lastComputed) { 278 result = value; 279 lastComputed = computed; 280 } 281 }); 282 return result; 283 }; 284 285 // Shuffle an array, using the modern version of the 286 // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/FisherâYates_shuffle). 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 // Sample **n** random values from a collection. 300 // If **n** is not specified, returns a single random element. 301 // The internal `guard` argument allows it to work with `map`. 302 _.sample = function(obj, n, guard) { 303 if (n == null || guard) { 304 if (obj.length !== +obj.length) obj = _.values(obj); 305 return obj[_.random(obj.length - 1)]; 306 } 307 return _.shuffle(obj).slice(0, Math.max(0, n)); 308 }; 309 310 // An internal function to generate lookup iterators. 311 var lookupIterator = function(value) { 312 if (value == null) return _.identity; 313 if (_.isFunction(value)) return value; 314 return _.property(value); 315 }; 316 317 // Sort the object's values by a criterion produced by an iterator. 318 _.sortBy = function(obj, iterator, context) { 319 iterator = lookupIterator(iterator); 320 return _.pluck(_.map(obj, function(value, index, list) { 321 return { 322 value: value, 323 index: index, 324 criteria: iterator.call(context, value, index, list) 325 }; 326 }).sort(function(left, right) { 327 var a = left.criteria; 328 var b = right.criteria; 329 if (a !== b) { 330 if (a > b || a === void 0) return 1; 331 if (a < b || b === void 0) return -1; 332 } 333 return left.index - right.index; 334 }), 'value'); 335 }; 336 337 // An internal function used for aggregate "group by" operations. 338 var group = function(behavior) { 339 return function(obj, iterator, context) { 340 var result = {}; 341 iterator = lookupIterator(iterator); 342 each(obj, function(value, index) { 343 var key = iterator.call(context, value, index, obj); 344 behavior(result, key, value); 345 }); 346 return result; 347 }; 348 }; 349 350 // Groups the object's values by a criterion. Pass either a string attribute 351 // to group by, or a function that returns the criterion. 352 _.groupBy = group(function(result, key, value) { 353 _.has(result, key) ? result[key].push(value) : result[key] = [value]; 354 }); 355 356 // Indexes the object's values by a criterion, similar to `groupBy`, but for 357 // when you know that your index values will be unique. 358 _.indexBy = group(function(result, key, value) { 359 result[key] = value; 360 }); 361 362 // Counts instances of an object that group by a certain criterion. Pass 363 // either a string attribute to count by, or a function that returns the 364 // criterion. 365 _.countBy = group(function(result, key) { 366 _.has(result, key) ? result[key]++ : result[key] = 1; 367 }); 368 369 // Use a comparator function to figure out the smallest index at which 370 // an object should be inserted so as to maintain order. Uses binary search. 371 _.sortedIndex = function(array, obj, iterator, context) { 372 iterator = lookupIterator(iterator); 373 var value = iterator.call(context, obj); 374 var low = 0, high = array.length; 375 while (low < high) { 376 var mid = (low + high) >>> 1; 377 iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid; 378 } 379 return low; 380 }; 381 382 // Safely create a real, live array from anything iterable. 383 _.toArray = function(obj) { 384 if (!obj) return []; 385 if (_.isArray(obj)) return slice.call(obj); 386 if (obj.length === +obj.length) return _.map(obj, _.identity); 387 return _.values(obj); 388 }; 389 390 // Return the number of elements in an object. 391 _.size = function(obj) { 392 if (obj == null) return 0; 393 return (obj.length === +obj.length) ? obj.length : _.keys(obj).length; 394 }; 395 396 // Array Functions 397 // --------------- 398 399 // Get the first element of an array. Passing **n** will return the first N 400 // values in the array. Aliased as `head` and `take`. The **guard** check 401 // allows it to work with `_.map`. 402 _.first = _.head = _.take = function(array, n, guard) { 403 if (array == null) return void 0; 404 if ((n == null) || guard) return array[0]; 405 if (n < 0) return []; 406 return slice.call(array, 0, n); 407 }; 408 409 // Returns everything but the last entry of the array. Especially useful on 410 // the arguments object. Passing **n** will return all the values in 411 // the array, excluding the last N. The **guard** check allows it to work with 412 // `_.map`. 413 _.initial = function(array, n, guard) { 414 return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n)); 415 }; 416 417 // Get the last element of an array. Passing **n** will return the last N 418 // values in the array. The **guard** check allows it to work with `_.map`. 419 _.last = function(array, n, guard) { 420 if (array == null) return void 0; 421 if ((n == null) || guard) return array[array.length - 1]; 422 return slice.call(array, Math.max(array.length - n, 0)); 423 }; 424 425 // Returns everything but the first entry of the array. Aliased as `tail` and `drop`. 426 // Especially useful on the arguments object. Passing an **n** will return 427 // the rest N values in the array. The **guard** 428 // check allows it to work with `_.map`. 429 _.rest = _.tail = _.drop = function(array, n, guard) { 430 return slice.call(array, (n == null) || guard ? 1 : n); 431 }; 432 433 // Trim out all falsy values from an array.
434 _.compact = function(array) { 435 return _.filter(array, _.identity); 436 }; 437 438 // Internal implementation of a recursive `flatten` function. 439 var flatten = function(input, shallow, output) { 440 if (shallow && _.every(input, _.isArray)) { 441 return concat.apply(output, input); 442 } 443 each(input, function(value) { 444 if (_.isArray(value) || _.isArguments(value)) { 445 shallow ? push.apply(output, value) : flatten(value, shallow, output); 446 } else { 447 output.push(value); 448 } 449 }); 450 return output; 451 }; 452 453 // Flatten out an array, either recursively (by default), or just one level. 454 _.flatten = function(array, shallow) { 455 return flatten(array, shallow, []); 456 }; 457 458 // Return a version of the array that does not contain the specified value(s). 459 _.without = function(array) { 460 return _.difference(array, slice.call(arguments, 1)); 461 }; 462 463 // Split an array into two arrays: one whose elements all satisfy the given 464 // predicate, and one whose elements all do not satisfy the predicate. 465 _.partition = function(array, predicate) { 466 var pass = [], fail = []; 467 each(array, function(elem) { 468 (predicate(elem) ? pass : fail).push(elem); 469 }); 470 return [pass, fail]; 471 }; 472 473 // Produce a duplicate-free version of the array. If the array has already 474 // been sorted, you have the option of using a faster algorithm. 475 // Aliased as `unique`. 476 _.uniq = _.unique = function(array, isSorted, iterator, context) { 477 if (_.isFunction(isSorted)) { 478 context = iterator; 479 iterator = isSorted; 480 isSorted = false; 481 } 482 var initial = iterator ? _.map(array, iterator, context) : array; 483 var results = []; 484 var seen = []; 485 each(initial, function(value, index) { 486 if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) { 487 seen.push(value); 488 results.push(array[index]); 489 } 490 }); 491 return results; 492 }; 493 494 // Produce an array that contains the union: each distinct element from all of 495 // the passed-in arrays. 496 _.union = function() { 497 return _.uniq(_.flatten(arguments, true)); 498 }; 499 500 // Produce an array that contains every item shared between all the 501 // passed-in arrays. 502 _.intersection = function(array) { 503 var rest = slice.call(arguments, 1); 504 return _.filter(_.uniq(array), function(item) { 505 return _.every(rest, function(other) { 506 return _.contains(other, item); 507 }); 508 }); 509 }; 510 511 // Take the difference between one array and a number of other arrays. 512 // Only the elements present in just the first array will remain. 513 _.difference = function(array) { 514 var rest = concat.apply(ArrayProto, slice.call(arguments, 1)); 515 return _.filter(array, function(value){ return !_.contains(rest, value); }); 516 }; 517 518 // Zip together multiple lists into a single array -- elements that share 519 // an index go together. 520 _.zip = function() { 521 var length = _.max(_.pluck(arguments, 'length').concat(0)); 522 var results = new Array(length); 523 for (var i = 0; i < length; i++) { 524 results[i] = _.pluck(arguments, '' + i); 525 } 526 return results; 527 }; 528 529 // Converts lists into objects. Pass either a single array of `[key, value]` 530 // pairs, or two parallel arrays of the same length -- one of keys, and one of 531 // the corresponding values. 532 _.object = function(list, values) { 533 if (list == null) return {}; 534 var result = {}; 535 for (var i = 0, length = list.length; i < length; i++) { 536 if (values) { 537 result[list[i]] = values[i]; 538 } else { 539 result[list[i][0]] = list[i][1]; 540 } 541 } 542 return result; 543 }; 544 545 // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**), 546 // we need this function. Return the position of the first occurrence of an 547 // item in an array, or -1 if the item is not included in the array. 548 // Delegates to **ECMAScript 5**'s native `indexOf` if available. 549 // If the array is large and already in sort order, pass `true` 550 // for **isSorted** to use binary search. 551 _.indexOf = function(array, item, isSorted) { 552 if (array == null) return -1; 553 var i = 0, length = array.length; 554 if (isSorted) { 555 if (typeof isSorted == 'number') { 556 i = (isSorted < 0 ? Math.max(0, length + isSorted) : isSorted); 557 } else { 558 i = _.sortedIndex(array, item); 559 return array[i] === item ? i : -1; 560 } 561 } 562 if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted); 563 for (; i < length; i++) if (array[i] === item) return i; 564 return -1; 565 }; 566 567 // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available. 568 _.lastIndexOf = function(array, item, from) { 569 if (array == null) return -1; 570 var hasIndex = from != null; 571 if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) { 572 return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item); 573 } 574 var i = (hasIndex ? from : array.length); 575 while (i--) if (array[i] === item) return i; 576 return -1; 577 }; 578 579 // Generate an integer Array containing an arithmetic progression. A port of 580 // the native Python `range()` function. See 581 // [the Python documentation](http://docs.python.org/library/functions.html#range). 582 _.range = function(start, stop, step) { 583 if (arguments.length <= 1) { 584 stop = start || 0; 585 start = 0; 586 } 587 step = arguments[2] || 1; 588 589 var length = Math.max(Math.ceil((stop - start) / step), 0); 590 var idx = 0; 591 var range = new Array(length); 592 593 while(idx < length) { 594 range[idx++] = start; 595 start += step; 596 } 597 598 return range; 599 }; 600 601 // Function (ahem) Functions 602 // ------------------ 603 604 // Reusable constructor function for prototype setting. 605 var ctor = function(){}; 606 607 // Create a function bound to a given object (assigning `this`, and arguments, 608 // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if 609 // available. 610 _.bind = function(func, context) { 611 var args, bound; 612 if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1)); 613 if (!_.isFunction(func)) throw new TypeError; 614 args = slice.call(arguments, 2); 615 return bound = function() { 616 if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments))); 617 ctor.prototype = func.prototype; 618 var self = new ctor; 619 ctor.prototype = null; 620 var result = func.apply(self, args.concat(slice.call(arguments))); 621 if (Object(result) === result) return result; 622 return self; 623 }; 624 }; 625 626 // Partially apply a function by creating a version that has had some of its 627 // arguments pre-filled, without changing its dynamic `this` context. _ acts 628 // as a placeholder, allowing any combination of arguments to be pre-filled. 629 _.partial = function(func) { 630 var boundArgs = slice.call(arguments, 1); 631 return function() { 632 var position = 0; 633 var args = boundArgs.slice(); 634 for (var i = 0, length = args.length; i < length; i++) { 635 if (args[i] === _) args[i] = arguments[position++]; 636 } 637 while (position < arguments.length) args.push(arguments[position++]); 638 return func.apply(this, args); 639 }; 640 }; 641 642 // Bind a number of an object's methods to that object. Remaining arguments
643 // are the method names to be bound. Useful for ensuring that all callbacks 644 // defined on an object belong to it. 645 _.bindAll = function(obj) { 646 var funcs = slice.call(arguments, 1); 647 if (funcs.length === 0) throw new Error('bindAll must be passed function names'); 648 each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); }); 649 return obj; 650 }; 651 652 // Memoize an expensive function by storing its results. 653 _.memoize = function(func, hasher) { 654 var memo = {}; 655 hasher || (hasher = _.identity); 656 return function() { 657 var key = hasher.apply(this, arguments); 658 return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments)); 659 }; 660 }; 661 662 // Delays a function for the given number of milliseconds, and then calls 663 // it with the arguments supplied. 664 _.delay = function(func, wait) { 665 var args = slice.call(arguments, 2); 666 return setTimeout(function(){ return func.apply(null, args); }, wait); 667 }; 668 669 // Defers a function, scheduling it to run after the current call stack has 670 // cleared. 671 _.defer = function(func) { 672 return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1))); 673 }; 674 675 // Returns a function, that, when invoked, will only be triggered at most once 676 // during a given window of time. Normally, the throttled function will run 677 // as much as it can, without ever going more than once per `wait` duration; 678 // but if you'd like to disable the execution on the leading edge, pass 679 // `{leading: false}`. To disable execution on the trailing edge, ditto. 680 _.throttle = function(func, wait, options) { 681 var context, args, result; 682 var timeout = null; 683 var previous = 0; 684 options || (options = {}); 685 var later = function() { 686 previous = options.leading === false ? 0 : _.now(); 687 timeout = null; 688 result = func.apply(context, args); 689 context = args = null; 690 }; 691 return function() { 692 var now = _.now(); 693 if (!previous && options.leading === false) previous = now; 694 var remaining = wait - (now - previous); 695 context = this; 696 args = arguments; 697 if (remaining <= 0) { 698 clearTimeout(timeout); 699 timeout = null; 700 previous = now; 701 result = func.apply(context, args); 702 context = args = null; 703 } else if (!timeout && options.trailing !== false) { 704 timeout = setTimeout(later, remaining); 705 } 706 return result; 707 }; 708 }; 709 710 // Returns a function, that, as long as it continues to be invoked, will not 711 // be triggered. The function will be called after it stops being called for 712 // N milliseconds. If `immediate` is passed, trigger the function on the 713 // leading edge, instead of the trailing. 714 _.debounce = function(func, wait, immediate) { 715 var timeout, args, context, timestamp, result; 716 717 var later = function() { 718 var last = _.now() - timestamp; 719 if (last < wait) { 720 timeout = setTimeout(later, wait - last); 721 } else { 722 timeout = null; 723 if (!immediate) { 724 result = func.apply(context, args); 725 context = args = null; 726 } 727 } 728 }; 729 730 return function() { 731 context = this; 732 args = arguments; 733 timestamp = _.now(); 734 var callNow = immediate && !timeout; 735 if (!timeout) { 736 timeout = setTimeout(later, wait); 737 } 738 if (callNow) { 739 result = func.apply(context, args); 740 context = args = null; 741 } 742 743 return result; 744 }; 745 }; 746 747 // Returns a function that will be executed at most one time, no matter how 748 // often you call it. Useful for lazy initialization. 749 _.once = function(func) { 750 var ran = false, memo; 751 return function() { 752 if (ran) return memo; 753 ran = true; 754 memo = func.apply(this, arguments); 755 func = null; 756 return memo; 757 }; 758 }; 759 760 // Returns the first function passed as an argument to the second, 761 // allowing you to adjust arguments, run code before and after, and 762 // conditionally execute the original function. 763 _.wrap = function(func, wrapper) { 764 return _.partial(wrapper, func); 765 }; 766 767 // Returns a function that is the composition of a list of functions, each 768 // consuming the return value of the function that follows. 769 _.compose = function() { 770 var funcs = arguments; 771 return function() { 772 var args = arguments; 773 for (var i = funcs.length - 1; i >= 0; i--) { 774 args = [funcs[i].apply(this, args)]; 775 } 776 return args[0]; 777 }; 778 }; 779 780 // Returns a function that will only be executed after being called N times. 781 _.after = function(times, func) { 782 return function() { 783 if (--times < 1) { 784 return func.apply(this, arguments); 785 } 786 }; 787 }; 788 789 // Object Functions 790 // ---------------- 791 792 // Retrieve the names of an object's properties. 793 // Delegates to **ECMAScript 5**'s native `Object.keys` 794 _.keys = function(obj) { 795 if (!_.isObject(obj)) return []; 796 if (nativeKeys) return nativeKeys(obj); 797 var keys = []; 798 for (var key in obj) if (_.has(obj, key)) keys.push(key); 799 return keys; 800 }; 801 802 // Retrieve the values of an object's properties. 803 _.values = function(obj) { 804 var keys = _.keys(obj); 805 var length = keys.length; 806 var values = new Array(length); 807 for (var i = 0; i < length; i++) { 808 values[i] = obj[keys[i]]; 809 } 810 return values; 811 }; 812 813 // Convert an object into a list of `[key, value]` pairs. 814 _.pairs = function(obj) { 815 var keys = _.keys(obj); 816 var length = keys.length; 817 var pairs = new Array(length); 818 for (var i = 0; i < length; i++) { 819 pairs[i] = [keys[i], obj[keys[i]]]; 820 } 821 return pairs; 822 }; 823 824 // Invert the keys and values of an object. The values must be serializable. 825 _.invert = function(obj) { 826 var result = {}; 827 var keys = _.keys(obj); 828 for (var i = 0, length = keys.length; i < length; i++) { 829 result[obj[keys[i]]] = keys[i]; 830 } 831 return result; 832 }; 833 834 // Return a sorted list of the function names available on the object. 835 // Aliased as `methods` 836 _.functions = _.methods = function(obj) { 837 var names = []; 838 for (var key in obj) { 839 if (_.isFunction(obj[key])) names.push(key); 840 } 841 return names.sort(); 842 }; 843 844 // Extend a given object with all the properties in passed-in object(s). 845 _.extend = function(obj) { 846 each(slice.call(arguments, 1), function(source) { 847 if (source) { 848 for (var prop in source) { 849 obj[prop] = source[prop]; 850 } 851 } 852 }); 853 return obj; 854 }; 855 856 // Return a copy of the object only containing the whitelisted properties. 857 _.pick = function(obj) { 858 var copy = {}; 859 var keys = concat.apply(ArrayProto, slice.call(arguments, 1)); 860 each(keys, function(key) { 861 if (key in obj) copy[key] = obj[key]; 862 }); 863 return copy; 864 }; 865
866 // Return a copy of the object without the blacklisted properties. 867 _.omit = function(obj) { 868 var copy = {}; 869 var keys = concat.apply(ArrayProto, slice.call(arguments, 1)); 870 for (var key in obj) { 871 if (!_.contains(keys, key)) copy[key] = obj[key]; 872 } 873 return copy; 874 }; 875 876 // Fill in a given object with default properties. 877 _.defaults = function(obj) { 878 each(slice.call(arguments, 1), function(source) { 879 if (source) { 880 for (var prop in source) { 881 if (obj[prop] === void 0) obj[prop] = source[prop]; 882 } 883 } 884 }); 885 return obj; 886 }; 887 888 // Create a (shallow-cloned) duplicate of an object. 889 _.clone = function(obj) { 890 if (!_.isObject(obj)) return obj; 891 return _.isArray(obj) ? obj.slice() : _.extend({}, obj); 892 }; 893 894 // Invokes interceptor with the obj, and then returns obj. 895 // The primary purpose of this method is to "tap into" a method chain, in 896 // order to perform operations on intermediate results within the chain. 897 _.tap = function(obj, interceptor) { 898 interceptor(obj); 899 return obj; 900 }; 901 902 // Internal recursive comparison function for `isEqual`. 903 var eq = function(a, b, aStack, bStack) { 904 // Identical objects are equal. `0 === -0`, but they aren't identical. 905 // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal). 906 if (a === b) return a !== 0 || 1 / a == 1 / b; 907 // A strict comparison is necessary because `null == undefined`. 908 if (a == null || b == null) return a === b; 909 // Unwrap any wrapped objects. 910 if (a instanceof _) a = a._wrapped; 911 if (b instanceof _) b = b._wrapped; 912 // Compare `[[Class]]` names. 913 var className = toString.call(a); 914 if (className != toString.call(b)) return false; 915 switch (className) { 916 // Strings, numbers, dates, and booleans are compared by value. 917 case '[object String]': 918 // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is 919 // equivalent to `new String("5")`. 920 return a == String(b); 921 case '[object Number]': 922 // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for 923 // other numeric values. 924 return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b); 925 case '[object Date]': 926 case '[object Boolean]': 927 // Coerce dates and booleans to numeric primitive values. Dates are compared by their 928 // millisecond representations. Note that invalid dates with millisecond representations 929 // of `NaN` are not equivalent. 930 return +a == +b; 931 // RegExps are compared by their source patterns and flags. 932 case '[object RegExp]': 933 return a.source == b.source && 934 a.global == b.global && 935 a.multiline == b.multiline && 936 a.ignoreCase == b.ignoreCase; 937 } 938 if (typeof a != 'object' || typeof b != 'object') return false; 939 // Assume equality for cyclic structures. The algorithm for detecting cyclic 940 // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`. 941 var length = aStack.length; 942 while (length--) { 943 // Linear search. Performance is inversely proportional to the number of 944 // unique nested structures. 945 if (aStack[length] == a) return bStack[length] == b; 946 } 947 // Objects with different constructors are not equivalent, but `Object`s 948 // from different frames are. 949 var aCtor = a.constructor, bCtor = b.constructor; 950 if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) && 951 _.isFunction(bCtor) && (bCtor instanceof bCtor)) 952 && ('constructor' in a && 'constructor' in b)) { 953 return false; 954 } 955 // Add the first object to the stack of traversed objects. 956 aStack.push(a); 957 bStack.push(b); 958 var size = 0, result = true; 959 // Recursively compare objects and arrays. 960 if (className == '[object Array]') { 961 // Compare array lengths to determine if a deep comparison is necessary. 962 size = a.length; 963 result = size == b.length; 964 if (result) { 965 // Deep compare the contents, ignoring non-numeric properties. 966 while (size--) { 967 if (!(result = eq(a[size], b[size], aStack, bStack))) break; 968 } 969 } 970 } else { 971 // Deep compare objects. 972 for (var key in a) { 973 if (_.has(a, key)) { 974 // Count the expected number of properties. 975 size++; 976 // Deep compare each member. 977 if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break; 978 } 979 } 980 // Ensure that both objects contain the same number of properties. 981 if (result) { 982 for (key in b) { 983 if (_.has(b, key) && !(size--)) break; 984 } 985 result = !size; 986 } 987 } 988 // Remove the first object from the stack of traversed objects. 989 aStack.pop(); 990 bStack.pop(); 991 return result; 992 }; 993 994 // Perform a deep comparison to check if two objects are equal. 995 _.isEqual = function(a, b) { 996 return eq(a, b, [], []); 997 }; 998 999 // Is a given array, string, or object empty? 1000 // An "empty" object has no enumerable own-properties. 1001 _.isEmpty = function(obj) { 1002 if (obj == null) return true; 1003 if (_.isArray(obj) || _.isString(obj)) return obj.length === 0; 1004 for (var key in obj) if (_.has(obj, key)) return false;
1005 return true; 1006 }; 1007 1008 // Is a given value a DOM element? 1009 _.isElement = function(obj) { 1010 return !!(obj && obj.nodeType === 1); 1011 }; 1012 1013 // Is a given value an array? 1014 // Delegates to ECMA5's native Array.isArray 1015 _.isArray = nativeIsArray || function(obj) { 1016 return toString.call(obj) == '[object Array]'; 1017 }; 1018 1019 // Is a given variable an object? 1020 _.isObject = function(obj) { 1021 return obj === Object(obj); 1022 }; 1023 1024 // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp. 1025 each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) { 1026 _['is' + name] = function(obj) { 1027 return toString.call(obj) == '[object ' + name + ']'; 1028 }; 1029 }); 1030 1031 // Define a fallback version of the method in browsers (ahem, IE), where 1032 // there isn't any inspectable "Arguments" type. 1033 if (!_.isArguments(arguments)) { 1034 _.isArguments = function(obj) { 1035 return !!(obj && _.has(obj, 'callee')); 1036 }; 1037 } 1038 1039 // Optimize `isFunction` if appropriate. 1040 if (typeof (/./) !== 'function') { 1041 _.isFunction = function(obj) { 1042 return typeof obj === 'function'; 1043 }; 1044 } 1045 1046 // Is a given object a finite number? 1047 _.isFinite = function(obj) { 1048 return isFinite(obj) && !isNaN(parseFloat(obj)); 1049 }; 1050 1051 // Is the given value `NaN`? (NaN is the only number which does not equal itself). 1052 _.isNaN = function(obj) { 1053 return _.isNumber(obj) && obj != +obj; 1054 }; 1055 1056 // Is a given value a boolean? 1057 _.isBoolean = function(obj) { 1058 return obj === true || obj === false || toString.call(obj) == '[object Boolean]'; 1059 }; 1060 1061 // Is a given value equal to null? 1062 _.isNull = function(obj) { 1063 return obj === null; 1064 }; 1065 1066 // Is a given variable undefined? 1067 _.isUndefined = function(obj) { 1068 return obj === void 0; 1069 }; 1070 1071 // Shortcut function for checking if an object has a given property directly 1072 // on itself (in other words, not on a prototype). 1073 _.has = function(obj, key) { 1074 return hasOwnProperty.call(obj, key); 1075 }; 1076 1077 // Utility Functions 1078 // ----------------- 1079 1080 // Run Underscore.js in *noConflict* mode, returning the `_` variable to its 1081 // previous owner. Returns a reference to the Underscore object. 1082 _.noConflict = function() { 1083 root._ = previousUnderscore; 1084 return this; 1085 }; 1086 1087 // Keep the identity function around for default iterators. 1088 _.identity = function(value) { 1089 return value; 1090 }; 1091 1092 _.constant = function(value) { 1093 return function () { 1094 return value; 1095 }; 1096 }; 1097 1098 _.property = function(key) { 1099 return function(obj) { 1100 return obj[key]; 1101 }; 1102 }; 1103 1104 // Returns a predicate for checking whether an object has a given set of `key:value` pairs. 1105 _.matches = function(attrs) { 1106 return function(obj) { 1107 if (obj === attrs) return true; //avoid comparing an object to itself. 1108 for (var key in attrs) { 1109 if (attrs[key] !== obj[key]) 1110 return false; 1111 } 1112 return true; 1113 } 1114 }; 1115 1116 // Run a function **n** times. 1117 _.times = function(n, iterator, context) { 1118 var accum = Array(Math.max(0, n)); 1119 for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i); 1120 return accum; 1121 }; 1122 1123 // Return a random integer between min and max (inclusive). 1124 _.random = function(min, max) { 1125 if (max == null) { 1126 max = min; 1127 min = 0; 1128 } 1129 return min + Math.floor(Math.random() * (max - min + 1)); 1130 }; 1131 1132 // A (possibly faster) way to get the current timestamp as an integer. 1133 _.now = Date.now || function() { return new Date().getTime(); }; 1134 1135 // List of HTML entities for escaping. 1136 var entityMap = { 1137 escape: { 1138 '&': '&', 1139 '<': '<', 1140 '>': '>', 1141 '"': '"', 1142 "'": ''' 1143 } 1144 }; 1145 entityMap.unescape = _.invert(entityMap.escape); 1146 1147 // Regexes containing the keys and values listed immediately above. 1148 var entityRegexes = { 1149 escape: new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'), 1150 unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g') 1151 }; 1152 1153 // Functions for escaping and unescaping strings to/from HTML interpolation. 1154 _.each(['escape', 'unescape'], function(method) { 1155 _[method] = function(string) { 1156 if (string == null) return ''; 1157 return ('' + string).replace(entityRegexes[method], function(match) { 1158 return entityMap[method][match]; 1159 }); 1160 }; 1161 }); 1162 1163 // If the value of the named `property` is a function then invoke it with the 1164 // `object` as context; otherwise, return it. 1165 _.result = function(object, property) { 1166 if (object == null) return void 0; 1167 var value = object[property]; 1168 return _.isFunction(value) ? value.call(object) : value; 1169 }; 1170 1171 // Add your own custom functions to the Underscore object. 1172 _.mixin = function(obj) { 1173 each(_.functions(obj), function(name) { 1174 var func = _[name] = obj[name]; 1175 _.prototype[name] = function() { 1176 var args = [this._wrapped]; 1177 push.apply(args, arguments); 1178 return result.call(this, func.apply(_, args)); 1179 }; 1180 }); 1181 }; 1182 1183 // Generate a unique integer id (unique within the entire client session). 1184 // Useful for temporary DOM ids. 1185 var idCounter = 0; 1186 _.uniqueId = function(prefix) { 1187 var id = ++idCounter + ''; 1188 return prefix ? prefix + id : id; 1189 }; 1190 1191 // By default, Underscore uses ERB-style template delimiters, change the 1192 // following template settings to use alternative delimiters. 1193 _.templateSettings = { 1194 evaluate : /<%([\s\S]+?)%>/g, 1195 interpolate : /<%=([\s\S]+?)%>/g, 1196 escape : /<%-([\s\S]+?)%>/g 1197 }; 1198 1199 // When customizing `templateSettings`, if you don't want to define an 1200 // interpolation, evaluation or escaping regex, we need one that is 1201 // guaranteed not to match. 1202 var noMatch = /(.)^/; 1203 1204 // Certain characters need to be escaped so that they can be put into a 1205 // string literal. 1206 var escapes = { 1207 "'": "'", 1208 '\\': '\\', 1209 '\r': 'r', 1210 '\n': 'n', 1211 '\t': 't', 1212 '\u2028': 'u2028', 1213 '\u2029': 'u2029' 1214 }; 1215 1216 var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g; 1217 1218 // JavaScript micro-templating, similar to John Resig's implementation. 1219 // Underscore templating handles arbitrary delimiters, preserves whitespace, 1220 // and correctly escapes quotes within interpolated code. 1221 _.template = function(text, data, settings) { 1222 var render; 1223 settings = _.defaults({}, settings, _.templateSettings); 1224 1225 // Combine delimiters into one regular expression via alternation. 1226 var matcher = new RegExp([
1227 (settings.escape || noMatch).source, 1228 (settings.interpolate || noMatch).source, 1229 (settings.evaluate || noMatch).source 1230 ].join('|') + '|$', 'g'); 1231 1232 // Compile the template source, escaping string literals appropriately. 1233 var index = 0; 1234 var source = "__p+='"; 1235 text.replace(matcher, function(match, escape, interpolate, evaluate, offset) { 1236 source += text.slice(index, offset) 1237 .replace(escaper, function(match) { return '\\' + escapes[match]; }); 1238 1239 if (escape) { 1240 source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'"; 1241 } 1242 if (interpolate) { 1243 source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'"; 1244 } 1245 if (evaluate) { 1246 source += "';\n" + evaluate + "\n__p+='"; 1247 } 1248 index = offset + match.length; 1249 return match; 1250 }); 1251 source += "';\n"; 1252 1253 // If a variable is not specified, place data values in local scope. 1254 if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n'; 1255 1256 source = "var __t,__p='',__j=Array.prototype.join," + 1257 "print=function(){__p+=__j.call(arguments,'');};\n" + 1258 source + "return __p;\n"; 1259 1260 try { 1261 render = new Function(settings.variable || 'obj', '_', source); 1262 } catch (e) { 1263 e.source = source; 1264 throw e; 1265 } 1266 1267 if (data) return render(data, _); 1268 var template = function(data) { 1269 return render.call(this, data, _); 1270 }; 1271 1272 // Provide the compiled function source as a convenience for precompilation. 1273 template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}'; 1274 1275 return template; 1276 }; 1277 1278 // Add a "chain" function, which will delegate to the wrapper. 1279 _.chain = function(obj) { 1280 return _(obj).chain(); 1281 }; 1282 1283 // OOP 1284 // --------------- 1285 // If Underscore is called as a function, it returns a wrapped object that 1286 // can be used OO-style. This wrapper holds altered versions of all the 1287 // underscore functions. Wrapped objects may be chained. 1288 1289 // Helper function to continue chaining intermediate results. 1290 var result = function(obj) { 1291 return this._chain ? _(obj).chain() : obj; 1292 }; 1293 1294 // Add all of the Underscore functions to the wrapper object. 1295 _.mixin(_); 1296 1297 // Add all mutator Array functions to the wrapper. 1298 each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) { 1299 var method = ArrayProto[name]; 1300 _.prototype[name] = function() { 1301 var obj = this._wrapped; 1302 method.apply(obj, arguments); 1303 if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0]; 1304 return result.call(this, obj); 1305 }; 1306 }); 1307 1308 // Add all accessor Array functions to the wrapper. 1309 each(['concat', 'join', 'slice'], function(name) { 1310 var method = ArrayProto[name]; 1311 _.prototype[name] = function() { 1312 return result.call(this, method.apply(this._wrapped, arguments)); 1313 }; 1314 }); 1315 1316 _.extend(_.prototype, { 1317 1318 // Start chaining a wrapped Underscore object. 1319 chain: function() { 1320 this._chain = true; 1321 return this; 1322 }, 1323 1324 // Extracts the result from a wrapped and chained object. 1325 value: function() { 1326 return this._wrapped; 1327 } 1328 1329 }); 1330 1331 // AMD registration happens at the end for compatibility with AMD loaders 1332 // that may not enforce next-turn semantics on modules. Even though general 1333 // practice for AMD registration is to be anonymous, underscore registers 1334 // as a named module because, like jQuery, it is a base library that is 1335 // popular enough to be bundled in a third party lib, but not be part of 1336 // an AMD load request. Those cases could generate an error when an 1337 // anonymous define() is called outside of a loader request. 1338 if (typeof define === 'function' && define.amd) { 1339 define('underscore', [], function() { 1340 return _; 1341 }); 1342 } 1343}).call(this);
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