1// Underscore.js 1.5.2 2// http://underscorejs.org 3// (c) 2009-2013 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 = '1.5.2'; 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; 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 }; 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.push(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.push(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 ? void 0 : []; 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 [WebKit Bug 80797](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, using the modern version of the 287 // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/FisherâYates_shuffle). 288 _.shuffle = function(obj) { 289 var rand; 290 var index = 0; 291 var shuffled = []; 292 each(obj, function(value) { 293 rand = _.random(index++); 294 shuffled[index - 1] = shuffled[rand]; 295 shuffled[rand] = value; 296 }); 297 return shuffled; 298 }; 299 300 // Sample **n** random values from an array. 301 // If **n** is not specified, returns a single random element from the array. 302 // The internal `guard` argument allows it to work with `map`. 303 _.sample = function(obj, n, guard) { 304 if (arguments.length < 2 || guard) { 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 return _.isFunction(value) ? value : function(obj){ return obj[value]; }; 313 }; 314 315 // Sort the object's values by a criterion produced by an iterator. 316 _.sortBy = function(obj, value, context) { 317 var iterator = lookupIterator(value); 318 return _.pluck(_.map(obj, function(value, index, list) { 319 return { 320 value: value, 321 index: index, 322 criteria: iterator.call(context, value, index, list) 323 }; 324 }).sort(function(left, right) { 325 var a = left.criteria; 326 var b = right.criteria; 327 if (a !== b) { 328 if (a > b || a === void 0) return 1; 329 if (a < b || b === void 0) return -1; 330 } 331 return left.index - right.index; 332 }), 'value'); 333 }; 334 335 // An internal function used for aggregate "group by" operations. 336 var group = function(behavior) { 337 return function(obj, value, context) { 338 var result = {}; 339 var iterator = value == null ? _.identity : lookupIterator(value); 340 each(obj, function(value, index) { 341 var key = iterator.call(context, value, index, obj); 342 behavior(result, key, value); 343 }); 344 return result; 345 }; 346 }; 347 348 // Groups the object's values by a criterion. Pass either a string attribute 349 // to group by, or a function that returns the criterion. 350 _.groupBy = group(function(result, key, value) { 351 (_.has(result, key) ? result[key] : (result[key] = [])).push(value); 352 }); 353 354 // Indexes the object's values by a criterion, similar to `groupBy`, but for 355 // when you know that your index values will be unique. 356 _.indexBy = group(function(result, key, value) { 357 result[key] = value; 358 }); 359 360 // Counts instances of an object that group by a certain criterion. Pass 361 // either a string attribute to count by, or a function that returns the 362 // criterion. 363 _.countBy = group(function(result, key) { 364 _.has(result, key) ? result[key]++ : result[key] = 1; 365 }); 366 367 // Use a comparator function to figure out the smallest index at which 368 // an object should be inserted so as to maintain order. Uses binary search. 369 _.sortedIndex = function(array, obj, iterator, context) { 370 iterator = iterator == null ? _.identity : lookupIterator(iterator); 371 var value = iterator.call(context, obj); 372 var low = 0, high = array.length; 373 while (low < high) { 374 var mid = (low + high) >>> 1; 375 iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid; 376 } 377 return low; 378 }; 379 380 // Safely create a real, live array from anything iterable. 381 _.toArray = function(obj) { 382 if (!obj) return []; 383 if (_.isArray(obj)) return slice.call(obj); 384 if (obj.length === +obj.length) return _.map(obj, _.identity); 385 return _.values(obj); 386 }; 387 388 // Return the number of elements in an object. 389 _.size = function(obj) { 390 if (obj == null) return 0; 391 return (obj.length === +obj.length) ? obj.length : _.keys(obj).length; 392 }; 393 394 // Array Functions 395 // --------------- 396 397 // Get the first element of an array. Passing **n** will return the first N 398 // values in the array. Aliased as `head` and `take`. The **guard** check 399 // allows it to work with `_.map`. 400 _.first = _.head = _.take = function(array, n, guard) { 401 if (array == null) return void 0; 402 return (n == null) || guard ? array[0] : slice.call(array, 0, n); 403 }; 404 405 // Returns everything but the last entry of the array. Especially useful on 406 // the arguments object. Passing **n** will return all the values in 407 // the array, excluding the last N. The **guard** check allows it to work with 408 // `_.map`. 409 _.initial = function(array, n, guard) { 410 return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n)); 411 }; 412 413 // Get the last element of an array. Passing **n** will return the last N 414 // values in the array. The **guard** check allows it to work with `_.map`. 415 _.last = function(array, n, guard) { 416 if (array == null) return void 0; 417 if ((n == null) || guard) { 418 return array[array.length - 1]; 419 } else { 420 return slice.call(array, Math.max(array.length - n, 0)); 421 } 422 }; 423 424 // Returns everything but the first entry of the array. Aliased as `tail` and `drop`. 425 // Especially useful on the arguments object. Passing an **n** will return 426 // the rest N values in the array. The **guard** 427 // check allows it to work with `_.map`. 428 _.rest = _.tail = _.drop = function(array, n, guard) { 429 return slice.call(array, (n == null) || guard ? 1 : n); 430 }; 431 432 // Trim out all falsy values from an array.
433 _.compact = function(array) { 434 return _.filter(array, _.identity); 435 }; 436 437 // Internal implementation of a recursive `flatten` function. 438 var flatten = function(input, shallow, output) { 439 if (shallow && _.every(input, _.isArray)) { 440 return concat.apply(output, input); 441 } 442 each(input, function(value) { 443 if (_.isArray(value) || _.isArguments(value)) { 444 shallow ? push.apply(output, value) : flatten(value, shallow, output); 445 } else { 446 output.push(value); 447 } 448 }); 449 return output; 450 }; 451 452 // Flatten out an array, either recursively (by default), or just one level. 453 _.flatten = function(array, shallow) { 454 return flatten(array, shallow, []); 455 }; 456 457 // Return a version of the array that does not contain the specified value(s). 458 _.without = function(array) { 459 return _.difference(array, slice.call(arguments, 1)); 460 }; 461 462 // Produce a duplicate-free version of the array. If the array has already 463 // been sorted, you have the option of using a faster algorithm. 464 // Aliased as `unique`. 465 _.uniq = _.unique = function(array, isSorted, iterator, context) { 466 if (_.isFunction(isSorted)) { 467 context = iterator; 468 iterator = isSorted; 469 isSorted = false; 470 } 471 var initial = iterator ? _.map(array, iterator, context) : array; 472 var results = []; 473 var seen = []; 474 each(initial, function(value, index) { 475 if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) { 476 seen.push(value); 477 results.push(array[index]); 478 } 479 }); 480 return results; 481 }; 482 483 // Produce an array that contains the union: each distinct element from all of 484 // the passed-in arrays. 485 _.union = function() { 486 return _.uniq(_.flatten(arguments, true)); 487 }; 488 489 // Produce an array that contains every item shared between all the 490 // passed-in arrays. 491 _.intersection = function(array) { 492 var rest = slice.call(arguments, 1); 493 return _.filter(_.uniq(array), function(item) { 494 return _.every(rest, function(other) { 495 return _.indexOf(other, item) >= 0; 496 }); 497 }); 498 }; 499 500 // Take the difference between one array and a number of other arrays. 501 // Only the elements present in just the first array will remain. 502 _.difference = function(array) { 503 var rest = concat.apply(ArrayProto, slice.call(arguments, 1)); 504 return _.filter(array, function(value){ return !_.contains(rest, value); }); 505 }; 506 507 // Zip together multiple lists into a single array -- elements that share 508 // an index go together. 509 _.zip = function() { 510 var length = _.max(_.pluck(arguments, "length").concat(0)); 511 var results = new Array(length); 512 for (var i = 0; i < length; i++) { 513 results[i] = _.pluck(arguments, '' + i); 514 } 515 return results; 516 }; 517 518 // Converts lists into objects. Pass either a single array of `[key, value]` 519 // pairs, or two parallel arrays of the same length -- one of keys, and one of 520 // the corresponding values. 521 _.object = function(list, values) { 522 if (list == null) return {}; 523 var result = {}; 524 for (var i = 0, length = list.length; i < length; i++) { 525 if (values) { 526 result[list[i]] = values[i]; 527 } else { 528 result[list[i][0]] = list[i][1]; 529 } 530 } 531 return result; 532 }; 533 534 // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**), 535 // we need this function. Return the position of the first occurrence of an 536 // item in an array, or -1 if the item is not included in the array. 537 // Delegates to **ECMAScript 5**'s native `indexOf` if available. 538 // If the array is large and already in sort order, pass `true` 539 // for **isSorted** to use binary search. 540 _.indexOf = function(array, item, isSorted) { 541 if (array == null) return -1; 542 var i = 0, length = array.length; 543 if (isSorted) { 544 if (typeof isSorted == 'number') { 545 i = (isSorted < 0 ? Math.max(0, length + isSorted) : isSorted); 546 } else { 547 i = _.sortedIndex(array, item); 548 return array[i] === item ? i : -1; 549 } 550 } 551 if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted); 552 for (; i < length; i++) if (array[i] === item) return i; 553 return -1; 554 }; 555 556 // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available. 557 _.lastIndexOf = function(array, item, from) { 558 if (array == null) return -1; 559 var hasIndex = from != null; 560 if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) { 561 return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item); 562 } 563 var i = (hasIndex ? from : array.length); 564 while (i--) if (array[i] === item) return i; 565 return -1; 566 }; 567 568 // Generate an integer Array containing an arithmetic progression. A port of 569 // the native Python `range()` function. See 570 // [the Python documentation](http://docs.python.org/library/functions.html#range). 571 _.range = function(start, stop, step) { 572 if (arguments.length <= 1) { 573 stop = start || 0; 574 start = 0; 575 } 576 step = arguments[2] || 1; 577 578 var length = Math.max(Math.ceil((stop - start) / step), 0); 579 var idx = 0; 580 var range = new Array(length); 581 582 while(idx < length) { 583 range[idx++] = start; 584 start += step; 585 } 586 587 return range; 588 }; 589 590 // Function (ahem) Functions 591 // ------------------ 592 593 // Reusable constructor function for prototype setting. 594 var ctor = function(){}; 595 596 // Create a function bound to a given object (assigning `this`, and arguments, 597 // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if 598 // available. 599 _.bind = function(func, context) { 600 var args, bound; 601 if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1)); 602 if (!_.isFunction(func)) throw new TypeError; 603 args = slice.call(arguments, 2); 604 return bound = function() { 605 if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments))); 606 ctor.prototype = func.prototype; 607 var self = new ctor; 608 ctor.prototype = null; 609 var result = func.apply(self, args.concat(slice.call(arguments))); 610 if (Object(result) === result) return result; 611 return self; 612 }; 613 }; 614 615 // Partially apply a function by creating a version that has had some of its 616 // arguments pre-filled, without changing its dynamic `this` context. 617 _.partial = function(func) { 618 var args = slice.call(arguments, 1); 619 return function() { 620 return func.apply(this, args.concat(slice.call(arguments))); 621 }; 622 }; 623 624 // Bind all of an object's methods to that object. Useful for ensuring that 625 // all callbacks defined on an object belong to it. 626 _.bindAll = function(obj) { 627 var funcs = slice.call(arguments, 1); 628 if (funcs.length === 0) throw new Error("bindAll must be passed function names"); 629 each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); }); 630 return obj; 631 }; 632 633 // Memoize an expensive function by storing its results. 634 _.memoize = function(func, hasher) { 635 var memo = {}; 636 hasher || (hasher = _.identity); 637 return function() { 638 var key = hasher.apply(this, arguments); 639 return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments)); 640 }; 641 }; 642 643 // Delays a function for the given number of milliseconds, and then calls 644 // it with the arguments supplied.
645 _.delay = function(func, wait) { 646 var args = slice.call(arguments, 2); 647 return setTimeout(function(){ return func.apply(null, args); }, wait); 648 }; 649 650 // Defers a function, scheduling it to run after the current call stack has 651 // cleared. 652 _.defer = function(func) { 653 return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1))); 654 }; 655 656 // Returns a function, that, when invoked, will only be triggered at most once 657 // during a given window of time. Normally, the throttled function will run 658 // as much as it can, without ever going more than once per `wait` duration; 659 // but if you'd like to disable the execution on the leading edge, pass 660 // `{leading: false}`. To disable execution on the trailing edge, ditto. 661 _.throttle = function(func, wait, options) { 662 var context, args, result; 663 var timeout = null; 664 var previous = 0; 665 options || (options = {}); 666 var later = function() { 667 previous = options.leading === false ? 0 : new Date; 668 timeout = null; 669 result = func.apply(context, args); 670 }; 671 return function() { 672 var now = new Date; 673 if (!previous && options.leading === false) previous = now; 674 var remaining = wait - (now - previous); 675 context = this; 676 args = arguments; 677 if (remaining <= 0) { 678 clearTimeout(timeout); 679 timeout = null; 680 previous = now; 681 result = func.apply(context, args); 682 } else if (!timeout && options.trailing !== false) { 683 timeout = setTimeout(later, remaining); 684 } 685 return result; 686 }; 687 }; 688 689 // Returns a function, that, as long as it continues to be invoked, will not 690 // be triggered. The function will be called after it stops being called for 691 // N milliseconds. If `immediate` is passed, trigger the function on the 692 // leading edge, instead of the trailing. 693 _.debounce = function(func, wait, immediate) { 694 var timeout, args, context, timestamp, result; 695 return function() { 696 context = this; 697 args = arguments; 698 timestamp = new Date(); 699 var later = function() { 700 var last = (new Date()) - timestamp; 701 if (last < wait) { 702 timeout = setTimeout(later, wait - last); 703 } else { 704 timeout = null; 705 if (!immediate) result = func.apply(context, args); 706 } 707 }; 708 var callNow = immediate && !timeout; 709 if (!timeout) { 710 timeout = setTimeout(later, wait); 711 } 712 if (callNow) result = func.apply(context, args); 713 return result; 714 }; 715 }; 716 717 // Returns a function that will be executed at most one time, no matter how 718 // often you call it. Useful for lazy initialization. 719 _.once = function(func) { 720 var ran = false, memo; 721 return function() { 722 if (ran) return memo; 723 ran = true; 724 memo = func.apply(this, arguments); 725 func = null; 726 return memo; 727 }; 728 }; 729 730 // Returns the first function passed as an argument to the second, 731 // allowing you to adjust arguments, run code before and after, and 732 // conditionally execute the original function. 733 _.wrap = function(func, wrapper) { 734 return function() { 735 var args = [func]; 736 push.apply(args, arguments); 737 return wrapper.apply(this, args); 738 }; 739 }; 740 741 // Returns a function that is the composition of a list of functions, each 742 // consuming the return value of the function that follows. 743 _.compose = function() { 744 var funcs = arguments; 745 return function() { 746 var args = arguments; 747 for (var i = funcs.length - 1; i >= 0; i--) { 748 args = [funcs[i].apply(this, args)]; 749 } 750 return args[0]; 751 }; 752 }; 753 754 // Returns a function that will only be executed after being called N times. 755 _.after = function(times, func) { 756 return function() { 757 if (--times < 1) { 758 return func.apply(this, arguments); 759 } 760 }; 761 }; 762 763 // Object Functions 764 // ---------------- 765 766 // Retrieve the names of an object's properties. 767 // Delegates to **ECMAScript 5**'s native `Object.keys` 768 _.keys = nativeKeys || function(obj) { 769 if (obj !== Object(obj)) throw new TypeError('Invalid object'); 770 var keys = []; 771 for (var key in obj) if (_.has(obj, key)) keys.push(key); 772 return keys; 773 }; 774 775 // Retrieve the values of an object's properties. 776 _.values = function(obj) { 777 var keys = _.keys(obj); 778 var length = keys.length; 779 var values = new Array(length); 780 for (var i = 0; i < length; i++) { 781 values[i] = obj[keys[i]]; 782 } 783 return values; 784 }; 785 786 // Convert an object into a list of `[key, value]` pairs. 787 _.pairs = function(obj) { 788 var keys = _.keys(obj); 789 var length = keys.length; 790 var pairs = new Array(length); 791 for (var i = 0; i < length; i++) { 792 pairs[i] = [keys[i], obj[keys[i]]]; 793 } 794 return pairs; 795 }; 796 797 // Invert the keys and values of an object. The values must be serializable. 798 _.invert = function(obj) { 799 var result = {}; 800 var keys = _.keys(obj); 801 for (var i = 0, length = keys.length; i < length; i++) { 802 result[obj[keys[i]]] = keys[i]; 803 } 804 return result; 805 }; 806 807 // Return a sorted list of the function names available on the object. 808 // Aliased as `methods` 809 _.functions = _.methods = function(obj) { 810 var names = []; 811 for (var key in obj) { 812 if (_.isFunction(obj[key])) names.push(key); 813 } 814 return names.sort(); 815 }; 816 817 // Extend a given object with all the properties in passed-in object(s). 818 _.extend = function(obj) { 819 each(slice.call(arguments, 1), function(source) { 820 if (source) { 821 for (var prop in source) { 822 obj[prop] = source[prop]; 823 } 824 } 825 }); 826 return obj; 827 }; 828 829 // Return a copy of the object only containing the whitelisted properties. 830 _.pick = function(obj) { 831 var copy = {}; 832 var keys = concat.apply(ArrayProto, slice.call(arguments, 1)); 833 each(keys, function(key) { 834 if (key in obj) copy[key] = obj[key]; 835 }); 836 return copy; 837 }; 838
839 // Return a copy of the object without the blacklisted properties. 840 _.omit = function(obj) { 841 var copy = {}; 842 var keys = concat.apply(ArrayProto, slice.call(arguments, 1)); 843 for (var key in obj) { 844 if (!_.contains(keys, key)) copy[key] = obj[key]; 845 } 846 return copy; 847 }; 848 849 // Fill in a given object with default properties. 850 _.defaults = function(obj) { 851 each(slice.call(arguments, 1), function(source) { 852 if (source) { 853 for (var prop in source) { 854 if (obj[prop] === void 0) obj[prop] = source[prop]; 855 } 856 } 857 }); 858 return obj; 859 }; 860 861 // Create a (shallow-cloned) duplicate of an object. 862 _.clone = function(obj) { 863 if (!_.isObject(obj)) return obj; 864 return _.isArray(obj) ? obj.slice() : _.extend({}, obj); 865 }; 866 867 // Invokes interceptor with the obj, and then returns obj. 868 // The primary purpose of this method is to "tap into" a method chain, in 869 // order to perform operations on intermediate results within the chain. 870 _.tap = function(obj, interceptor) { 871 interceptor(obj); 872 return obj; 873 }; 874 875 // Internal recursive comparison function for `isEqual`. 876 var eq = function(a, b, aStack, bStack) { 877 // Identical objects are equal. `0 === -0`, but they aren't identical. 878 // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal). 879 if (a === b) return a !== 0 || 1 / a == 1 / b; 880 // A strict comparison is necessary because `null == undefined`. 881 if (a == null || b == null) return a === b; 882 // Unwrap any wrapped objects. 883 if (a instanceof _) a = a._wrapped; 884 if (b instanceof _) b = b._wrapped; 885 // Compare `[[Class]]` names. 886 var className = toString.call(a); 887 if (className != toString.call(b)) return false; 888 switch (className) { 889 // Strings, numbers, dates, and booleans are compared by value. 890 case '[object String]': 891 // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is 892 // equivalent to `new String("5")`. 893 return a == String(b); 894 case '[object Number]': 895 // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for 896 // other numeric values. 897 return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b); 898 case '[object Date]': 899 case '[object Boolean]': 900 // Coerce dates and booleans to numeric primitive values. Dates are compared by their 901 // millisecond representations. Note that invalid dates with millisecond representations 902 // of `NaN` are not equivalent. 903 return +a == +b; 904 // RegExps are compared by their source patterns and flags. 905 case '[object RegExp]': 906 return a.source == b.source && 907 a.global == b.global && 908 a.multiline == b.multiline && 909 a.ignoreCase == b.ignoreCase; 910 } 911 if (typeof a != 'object' || typeof b != 'object') return false; 912 // Assume equality for cyclic structures. The algorithm for detecting cyclic 913 // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`. 914 var length = aStack.length; 915 while (length--) { 916 // Linear search. Performance is inversely proportional to the number of 917 // unique nested structures. 918 if (aStack[length] == a) return bStack[length] == b; 919 } 920 // Objects with different constructors are not equivalent, but `Object`s 921 // from different frames are. 922 var aCtor = a.constructor, bCtor = b.constructor; 923 if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) && 924 _.isFunction(bCtor) && (bCtor instanceof bCtor))) { 925 return false; 926 } 927 // Add the first object to the stack of traversed objects. 928 aStack.push(a); 929 bStack.push(b); 930 var size = 0, result = true; 931 // Recursively compare objects and arrays. 932 if (className == '[object Array]') { 933 // Compare array lengths to determine if a deep comparison is necessary. 934 size = a.length; 935 result = size == b.length; 936 if (result) { 937 // Deep compare the contents, ignoring non-numeric properties. 938 while (size--) { 939 if (!(result = eq(a[size], b[size], aStack, bStack))) break; 940 } 941 } 942 } else { 943 // Deep compare objects. 944 for (var key in a) { 945 if (_.has(a, key)) { 946 // Count the expected number of properties. 947 size++; 948 // Deep compare each member. 949 if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break; 950 } 951 } 952 // Ensure that both objects contain the same number of properties. 953 if (result) { 954 for (key in b) { 955 if (_.has(b, key) && !(size--)) break; 956 } 957 result = !size; 958 } 959 } 960 // Remove the first object from the stack of traversed objects. 961 aStack.pop(); 962 bStack.pop(); 963 return result; 964 }; 965 966 // Perform a deep comparison to check if two objects are equal. 967 _.isEqual = function(a, b) { 968 return eq(a, b, [], []); 969 }; 970 971 // Is a given array, string, or object empty? 972 // An "empty" object has no enumerable own-properties. 973 _.isEmpty = function(obj) { 974 if (obj == null) return true; 975 if (_.isArray(obj) || _.isString(obj)) return obj.length === 0; 976 for (var key in obj) if (_.has(obj, key)) return false;
977 return true; 978 }; 979 980 // Is a given value a DOM element? 981 _.isElement = function(obj) { 982 return !!(obj && obj.nodeType === 1); 983 }; 984 985 // Is a given value an array? 986 // Delegates to ECMA5's native Array.isArray 987 _.isArray = nativeIsArray || function(obj) { 988 return toString.call(obj) == '[object Array]'; 989 }; 990 991 // Is a given variable an object? 992 _.isObject = function(obj) { 993 return obj === Object(obj); 994 }; 995 996 // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp. 997 each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) { 998 _['is' + name] = function(obj) { 999 return toString.call(obj) == '[object ' + name + ']'; 1000 }; 1001 }); 1002 1003 // Define a fallback version of the method in browsers (ahem, IE), where 1004 // there isn't any inspectable "Arguments" type. 1005 if (!_.isArguments(arguments)) { 1006 _.isArguments = function(obj) { 1007 return !!(obj && _.has(obj, 'callee')); 1008 }; 1009 } 1010 1011 // Optimize `isFunction` if appropriate. 1012 if (typeof (/./) !== 'function') { 1013 _.isFunction = function(obj) { 1014 return typeof obj === 'function'; 1015 }; 1016 } 1017 1018 // Is a given object a finite number? 1019 _.isFinite = function(obj) { 1020 return isFinite(obj) && !isNaN(parseFloat(obj)); 1021 }; 1022 1023 // Is the given value `NaN`? (NaN is the only number which does not equal itself). 1024 _.isNaN = function(obj) { 1025 return _.isNumber(obj) && obj != +obj; 1026 }; 1027 1028 // Is a given value a boolean? 1029 _.isBoolean = function(obj) { 1030 return obj === true || obj === false || toString.call(obj) == '[object Boolean]'; 1031 }; 1032 1033 // Is a given value equal to null? 1034 _.isNull = function(obj) { 1035 return obj === null; 1036 }; 1037 1038 // Is a given variable undefined? 1039 _.isUndefined = function(obj) { 1040 return obj === void 0; 1041 }; 1042 1043 // Shortcut function for checking if an object has a given property directly 1044 // on itself (in other words, not on a prototype). 1045 _.has = function(obj, key) { 1046 return hasOwnProperty.call(obj, key); 1047 }; 1048 1049 // Utility Functions 1050 // ----------------- 1051 1052 // Run Underscore.js in *noConflict* mode, returning the `_` variable to its 1053 // previous owner. Returns a reference to the Underscore object. 1054 _.noConflict = function() { 1055 root._ = previousUnderscore; 1056 return this; 1057 }; 1058 1059 // Keep the identity function around for default iterators. 1060 _.identity = function(value) { 1061 return value; 1062 }; 1063 1064 // Run a function **n** times. 1065 _.times = function(n, iterator, context) { 1066 var accum = Array(Math.max(0, n)); 1067 for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i); 1068 return accum; 1069 }; 1070 1071 // Return a random integer between min and max (inclusive). 1072 _.random = function(min, max) { 1073 if (max == null) { 1074 max = min; 1075 min = 0; 1076 } 1077 return min + Math.floor(Math.random() * (max - min + 1)); 1078 }; 1079 1080 // List of HTML entities for escaping. 1081 var entityMap = { 1082 escape: { 1083 '&': '&', 1084 '<': '<', 1085 '>': '>', 1086 '"': '"', 1087 "'": ''' 1088 } 1089 }; 1090 entityMap.unescape = _.invert(entityMap.escape); 1091 1092 // Regexes containing the keys and values listed immediately above. 1093 var entityRegexes = { 1094 escape: new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'), 1095 unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g') 1096 }; 1097 1098 // Functions for escaping and unescaping strings to/from HTML interpolation. 1099 _.each(['escape', 'unescape'], function(method) { 1100 _[method] = function(string) { 1101 if (string == null) return ''; 1102 return ('' + string).replace(entityRegexes[method], function(match) { 1103 return entityMap[method][match]; 1104 }); 1105 }; 1106 }); 1107 1108 // If the value of the named `property` is a function then invoke it with the 1109 // `object` as context; otherwise, return it. 1110 _.result = function(object, property) { 1111 if (object == null) return void 0; 1112 var value = object[property]; 1113 return _.isFunction(value) ? value.call(object) : value; 1114 }; 1115 1116 // Add your own custom functions to the Underscore object. 1117 _.mixin = function(obj) { 1118 each(_.functions(obj), function(name) { 1119 var func = _[name] = obj[name]; 1120 _.prototype[name] = function() { 1121 var args = [this._wrapped]; 1122 push.apply(args, arguments); 1123 return result.call(this, func.apply(_, args)); 1124 }; 1125 }); 1126 }; 1127 1128 // Generate a unique integer id (unique within the entire client session). 1129 // Useful for temporary DOM ids. 1130 var idCounter = 0; 1131 _.uniqueId = function(prefix) { 1132 var id = ++idCounter + ''; 1133 return prefix ? prefix + id : id; 1134 }; 1135 1136 // By default, Underscore uses ERB-style template delimiters, change the 1137 // following template settings to use alternative delimiters. 1138 _.templateSettings = { 1139 evaluate : /<%([\s\S]+?)%>/g, 1140 interpolate : /<%=([\s\S]+?)%>/g, 1141 escape : /<%-([\s\S]+?)%>/g 1142 }; 1143 1144 // When customizing `templateSettings`, if you don't want to define an 1145 // interpolation, evaluation or escaping regex, we need one that is 1146 // guaranteed not to match. 1147 var noMatch = /(.)^/; 1148 1149 // Certain characters need to be escaped so that they can be put into a 1150 // string literal. 1151 var escapes = { 1152 "'": "'", 1153 '\\': '\\', 1154 '\r': 'r', 1155 '\n': 'n', 1156 '\t': 't', 1157 '\u2028': 'u2028', 1158 '\u2029': 'u2029' 1159 }; 1160 1161 var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g; 1162 1163 // JavaScript micro-templating, similar to John Resig's implementation. 1164 // Underscore templating handles arbitrary delimiters, preserves whitespace, 1165 // and correctly escapes quotes within interpolated code. 1166 _.template = function(text, data, settings) { 1167 var render; 1168 settings = _.defaults({}, settings, _.templateSettings); 1169 1170 // Combine delimiters into one regular expression via alternation. 1171 var matcher = new RegExp([
1172 (settings.escape || noMatch).source, 1173 (settings.interpolate || noMatch).source, 1174 (settings.evaluate || noMatch).source 1175 ].join('|') + '|$', 'g'); 1176 1177 // Compile the template source, escaping string literals appropriately. 1178 var index = 0; 1179 var source = "__p+='"; 1180 text.replace(matcher, function(match, escape, interpolate, evaluate, offset) { 1181 source += text.slice(index, offset) 1182 .replace(escaper, function(match) { return '\\' + escapes[match]; }); 1183 1184 if (escape) { 1185 source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'"; 1186 } 1187 if (interpolate) { 1188 source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'"; 1189 } 1190 if (evaluate) { 1191 source += "';\n" + evaluate + "\n__p+='"; 1192 } 1193 index = offset + match.length; 1194 return match; 1195 }); 1196 source += "';\n"; 1197 1198 // If a variable is not specified, place data values in local scope. 1199 if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n'; 1200 1201 source = "var __t,__p='',__j=Array.prototype.join," + 1202 "print=function(){__p+=__j.call(arguments,'');};\n" + 1203 source + "return __p;\n"; 1204 1205 try { 1206 render = new Function(settings.variable || 'obj', '_', source); 1207 } catch (e) { 1208 e.source = source; 1209 throw e; 1210 } 1211 1212 if (data) return render(data, _); 1213 var template = function(data) { 1214 return render.call(this, data, _); 1215 }; 1216 1217 // Provide the compiled function source as a convenience for precompilation. 1218 template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}'; 1219 1220 return template; 1221 }; 1222 1223 // Add a "chain" function, which will delegate to the wrapper. 1224 _.chain = function(obj) { 1225 return _(obj).chain(); 1226 }; 1227 1228 // OOP 1229 // --------------- 1230 // If Underscore is called as a function, it returns a wrapped object that 1231 // can be used OO-style. This wrapper holds altered versions of all the 1232 // underscore functions. Wrapped objects may be chained. 1233 1234 // Helper function to continue chaining intermediate results. 1235 var result = function(obj) { 1236 return this._chain ? _(obj).chain() : obj; 1237 }; 1238 1239 // Add all of the Underscore functions to the wrapper object. 1240 _.mixin(_); 1241 1242 // Add all mutator Array functions to the wrapper. 1243 each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) { 1244 var method = ArrayProto[name]; 1245 _.prototype[name] = function() { 1246 var obj = this._wrapped; 1247 method.apply(obj, arguments); 1248 if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0]; 1249 return result.call(this, obj); 1250 }; 1251 }); 1252 1253 // Add all accessor Array functions to the wrapper. 1254 each(['concat', 'join', 'slice'], function(name) { 1255 var method = ArrayProto[name]; 1256 _.prototype[name] = function() { 1257 return result.call(this, method.apply(this._wrapped, arguments)); 1258 }; 1259 }); 1260 1261 _.extend(_.prototype, { 1262 1263 // Start chaining a wrapped Underscore object. 1264 chain: function() { 1265 this._chain = true; 1266 return this; 1267 }, 1268 1269 // Extracts the result from a wrapped and chained object. 1270 value: function() { 1271 return this._wrapped; 1272 } 1273 1274 }); 1275 1276}).call(this);
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