1// Underscore.js 1.1.7 2// (c) 2011 Jeremy Ashkenas, DocumentCloud Inc. 3// Underscore is freely distributable under the MIT license. 4// Portions of Underscore are inspired or borrowed from Prototype, 5// Oliver Steele's Functional, and John Resig's Micro-Templating. 6// For all details and documentation: 7// http://documentcloud.github.com/underscore 8 9(function() { 10 11 // Baseline setup 12 // -------------- 13 14 // Establish the root object, `window` in the browser, or `global` on the server. 15 var root = this; 16 17 // Save the previous value of the `_` variable. 18 var previousUnderscore = root._; 19 20 // Establish the object that gets returned to break out of a loop iteration. 21 var breaker = {}; 22 23 // Save bytes in the minified (but not gzipped) version: 24 var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype; 25 26 // Create quick reference variables for speed access to core prototypes. 27 var slice = ArrayProto.slice, 28 unshift = ArrayProto.unshift, 29 toString = ObjProto.toString, 30 hasOwnProperty = ObjProto.hasOwnProperty; 31 32 // All **ECMAScript 5** native function implementations that we hope to use 33 // are declared here. 34 var 35 nativeForEach = ArrayProto.forEach, 36 nativeMap = ArrayProto.map, 37 nativeReduce = ArrayProto.reduce, 38 nativeReduceRight = ArrayProto.reduceRight, 39 nativeFilter = ArrayProto.filter, 40 nativeEvery = ArrayProto.every, 41 nativeSome = ArrayProto.some, 42 nativeIndexOf = ArrayProto.indexOf, 43 nativeLastIndexOf = ArrayProto.lastIndexOf, 44 nativeIsArray = Array.isArray, 45 nativeKeys = Object.keys, 46 nativeBind = FuncProto.bind; 47 48 // Create a safe reference to the Underscore object for use below. 49 var _ = function(obj) { return new wrapper(obj); }; 50 51 // Export the Underscore object for **CommonJS**, with backwards-compatibility 52 // for the old `require()` API. If we're not in CommonJS, add `_` to the 53 // global object. 54 if (typeof module !== 'undefined' && module.exports) { 55 module.exports = _; 56 _._ = _; 57 } else { 58 // Exported as a string, for Closure Compiler "advanced" mode. 59 root['_'] = _; 60 } 61 62 // Current version. 63 _.VERSION = '1.1.7'; 64 65 // Collection Functions 66 // -------------------- 67 68 // The cornerstone, an `each` implementation, aka `forEach`. 69 // Handles objects with the built-in `forEach`, arrays, and raw objects. 70 // Delegates to **ECMAScript 5**'s native `forEach` if available. 71 var each = _.each = _.forEach = function(obj, iterator, context) { 72 if (obj == null) return; 73 if (nativeForEach && obj.forEach === nativeForEach) { 74 obj.forEach(iterator, context); 75 } else if (obj.length === +obj.length) { 76 for (var i = 0, l = obj.length; i < l; i++) { 77 if (i in obj && iterator.call(context, obj[i], i, obj) === breaker) return; 78 } 79 } else { 80 for (var key in obj) { 81 if (hasOwnProperty.call(obj, key)) { 82 if (iterator.call(context, obj[key], key, obj) === breaker) return; 83 } 84 } 85 } 86 }; 87 88 // Return the results of applying the iterator to each element. 89 // Delegates to **ECMAScript 5**'s native `map` if available. 90 _.map = function(obj, iterator, context) { 91 var results = []; 92 if (obj == null) return results; 93 if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context); 94 each(obj, function(value, index, list) { 95 results[results.length] = iterator.call(context, value, index, list); 96 }); 97 return results; 98 }; 99 100 // **Reduce** builds up a single result from a list of values, aka `inject`, 101 // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available. 102 _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) { 103 var initial = memo !== void 0; 104 if (obj == null) obj = []; 105 if (nativeReduce && obj.reduce === nativeReduce) { 106 if (context) iterator = _.bind(iterator, context); 107 return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator); 108 } 109 each(obj, function(value, index, list) { 110 if (!initial) { 111 memo = value; 112 initial = true; 113 } else { 114 memo = iterator.call(context, memo, value, index, list); 115 } 116 }); 117 if (!initial) throw new TypeError("Reduce of empty array with
117no initial value"); 118 return memo; 119 }; 120 121 // The right-associative version of reduce, also known as `foldr`. 122 // Delegates to **ECMAScript 5**'s native `reduceRight` if available. 123 _.reduceRight = _.foldr = function(obj, iterator, memo, context) { 124 if (obj == null) obj = []; 125 if (nativeReduceRight && obj.reduceRight === nativeReduceRight) { 126 if (context) iterator = _.bind(iterator, context); 127 return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator); 128 } 129 var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse(); 130 return _.reduce(reversed, iterator, memo, context); 131 }; 132 133 // Return the first value which passes a truth test. Aliased as `detect`. 134 _.find = _.detect = function(obj, iterator, context) { 135 var result; 136 any(obj, function(value, index, list) { 137 if (iterator.call(context, value, index, list)) { 138 result = value; 139 return true; 140 } 141 }); 142 return result; 143 }; 144 145 // Return all the elements that pass a truth test. 146 // Delegates to **ECMAScript 5**'s native `filter` if available. 147 // Aliased as `select`. 148 _.filter = _.select = function(obj, iterator, context) { 149 var results = []; 150 if (obj == null) return results; 151 if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context); 152 each(obj, function(value, index, list) { 153 if (iterator.call(context, value, index, list)) results[results.length] = value; 154 }); 155 return results; 156 }; 157 158 // Return all the elements for which a truth test fails. 159 _.reject = function(obj, iterator, context) { 160 var results = []; 161 if (obj == null) return results; 162 each(obj, function(value, index, list) { 163 if (!iterator.call(context, value, index, list)) results[results.length] = value; 164 }); 165 return results; 166 }; 167 168 // Determine whether all of the elements match a truth test. 169 // Delegates to **ECMAScript 5**'s native `every` if available. 170 // Aliased as `all`. 171 _.every = _.all = function(obj, iterator, context) { 172 var result = true; 173 if (obj == null) return result; 174 if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context); 175 each(obj, function(value, index, list) { 176 if (!(result = result && iterator.call(context, value, index, list))) return breaker; 177 }); 178 return result; 179 }; 180 181 // Determine if at least one element in the object matches a truth test. 182 // Delegates to **ECMAScript 5**'s native `some` if available. 183 // Aliased as `any`. 184 var any = _.some = _.any = function(obj, iterator, context) { 185 iterator = iterator || _.identity; 186 var result = false;
187 if (obj == null) return result; 188 if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context); 189 each(obj, function(value, index, list) { 190 if (result |= iterator.call(context, value, index, list)) return breaker; 191 }); 192 return !!result; 193 }; 194 195 // Determine if a given value is included in the array or object using `===`. 196 // Aliased as `contains`. 197 _.include = _.contains = function(obj, target) { 198 var found = false; 199 if (obj == null) return found; 200 if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1; 201 any(obj, function(value) { 202 if (found = value === target) return true; 203 }); 204 return found; 205 }; 206 207 // Invoke a method (with arguments) on every item in a collection. 208 _.invoke = function(obj, method) { 209 var args = slice.call(arguments, 2); 210 return _.map(obj, function(value) { 211 return (method.call ? method || value : value[method]).apply(value, args); 212 }); 213 }; 214 215 // Convenience version of a common use case of `map`: fetching a property. 216 _.pluck = function(obj, key) { 217 return _.map(obj, function(value){ return value[key]; }); 218 }; 219 220 // Return the maximum element or (element-based computation). 221 _.max = function(obj, iterator, context) { 222 if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj); 223 var result = {computed : -Infinity}; 224 each(obj, function(value, index, list) { 225 var computed = iterator ? iterator.call(context, value, index, list) : value; 226 computed >= result.computed && (result = {value : value, computed : computed}); 227 }); 228 return result.value; 229 }; 230 231 // Return the minimum element (or element-based computation). 232 _.min = function(obj, iterator, context) { 233 if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj); 234 var result = {computed : Infinity}; 235 each(obj, function(value, index, list) { 236 var computed = iterator ? iterator.call(context, value, index, list) : value; 237 computed < result.computed && (result = {value : value, computed : computed}); 238 }); 239 return result.value; 240 }; 241 242 // Sort the object's values by a criterion produced by an iterator. 243 _.sortBy = function(obj, iterator, context) { 244 return _.pluck(_.map(obj, function(value, index, list) { 245 return { 246 value : value, 247 criteria : iterator.call(context, value, index, list) 248 }; 249 }).sort(function(left, right) { 250 var a = left.criteria, b = right.criteria; 251 return a < b ? -1 : a > b ? 1 : 0; 252 }), 'value'); 253 }; 254 255 // Groups the object's values by a criterion produced by an iterator 256 _.groupBy = function(obj, iterator) { 257 var result = {}; 258 each(obj, function(value, index) { 259 var key = iterator(value, index); 260 (result[key] || (result[key] = [])).push(value); 261 }); 262 return result; 263 }; 264 265 // Use a comparator function to figure out at what index an object should 266 // be inserted so as to maintain order. Uses binary search. 267 _.sortedIndex = function(array, obj, iterator) { 268 iterator || (iterator = _.identity); 269 var low = 0, high = array.length; 270 while (low < high) { 271 var mid = (low + high) >> 1; 272 iterator(array[mid]) < iterator(obj) ? low = mid + 1 : high = mid; 273 } 274 return low; 275 }; 276 277 // Safely convert anything iterable into a real, live array. 278 _.toArray = function(iterable) { 279 if (!iterable) return []; 280 if (iterable.toArray) return iterable.toArray(); 281 if (_.isArray(iterable)) return slice.call(iterable); 282 if (_.isArguments(iterable)) return slice.call(iterable); 283 return _.values(iterable); 284 }; 285 286 // Return the number of elements in an object. 287 _.size = function(obj) { 288 return _.toArray(obj).length; 289 }; 290 291 // Array Functions 292 // --------------- 293 294 // Get the first element of an array. Passing **n** will return the first N 295 // values in the array. Aliased as `head`. The **guard** check allows it to work 296 // with `_.map`. 297 _.first = _.head = function(array, n, guard) { 298 return (n != null) && !guard ? slice.call(array, 0, n) : array[0]; 299 }; 300 301 // Returns everything but the first entry of the array. Aliased as `tail`. 302 // Especially useful on the arguments object. Passing an **index** will return 303 // the rest of the values in the array from that index onward. The **guard** 304 // check allows it to work with `_.map`. 305 _.rest = _.tail = function(array, index, guard) { 306 return slice.call(array, (index == null) || guard ? 1 : index); 307 }; 308 309 // Get the last element of an array.
310 _.last = function(array) { 311 return array[array.length - 1]; 312 }; 313 314 // Trim out all falsy values from an array. 315 _.compact = function(array) { 316 return _.filter(array, function(value){ return !!value; }); 317 }; 318 319 // Return a completely flattened version of an array. 320 _.flatten = function(array) { 321 return _.reduce(array, function(memo, value) { 322 if (_.isArray(value)) return memo.concat(_.flatten(value)); 323 memo[memo.length] = value; 324 return memo; 325 }, []); 326 }; 327 328 // Return a version of the array that does not contain the specified value(s). 329 _.without = function(array) { 330 return _.difference(array, slice.call(arguments, 1)); 331 }; 332 333 // Produce a duplicate-free version of the array. If the array has already 334 // been sorted, you have the option of using a faster algorithm. 335 // Aliased as `unique`. 336 _.uniq = _.unique = function(array, isSorted, iterator) { 337 var initial = iterator ? _.map(array, iterator) : array; 338 var result = []; 339 _.reduce(initial, function(memo, el, i) { 340 if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) { 341 memo[memo.length] = el; 342 result[result.length] = array[i]; 343 } 344 return memo; 345 }, []); 346 return result; 347 }; 348 349 // Produce an array that contains the union: each distinct element from all of 350 // the passed-in arrays. 351 _.union = function() { 352 return _.uniq(_.flatten(arguments)); 353 }; 354 355 // Produce an array that contains every item shared between all the 356 // passed-in arrays. (Aliased as "intersect" for back-compat.) 357 _.intersection = _.intersect = function(array) { 358 var rest = slice.call(arguments, 1); 359 return _.filter(_.uniq(array), function(item) { 360 return _.every(rest, function(other) { 361 return _.indexOf(other, item) >= 0; 362 }); 363 }); 364 }; 365 366 // Take the difference between one array and another. 367 // Only the elements present in just the first array will remain. 368 _.difference = function(array, other) { 369 return _.filter(array, function(value){ return !_.include(other, value); }); 370 }; 371 372 // Zip together multiple lists into a single array -- elements that share 373 // an index go together. 374 _.zip = function() { 375 var args = slice.call(arguments); 376 var length = _.max(_.pluck(args, 'length')); 377 var results = new Array(length); 378 for (var i = 0; i < length; i++) results[i] = _.pluck(args, "" + i); 379 return results; 380 }; 381 382 // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**), 383 // we need this function. Return the position of the first occurrence of an 384 // item in an array, or -1 if the item is not included in the array. 385 // Delegates to **ECMAScript 5**'s native `indexOf` if available. 386 // If the array is large and already in sort order, pass `true` 387 // for **isSorted** to use binary search. 388 _.indexOf = function(array, item, isSorted) { 389 if (array == null) return -1; 390 var i, l; 391 if (isSorted) { 392 i = _.sortedIndex(array, item); 393 return array[i] === item ? i : -1; 394 } 395 if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item); 396 for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i; 397 return -1; 398 }; 399 400 401 // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available. 402 _.lastIndexOf = function(array, item) { 403 if (array == null) return -1; 404 if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item); 405 var i = array.length; 406 while (i--) if (array[i] === item) return i; 407 return -1; 408 }; 409 410 // Generate an integer Array containing an arithmetic progression. A port of 411 // the native Python `range()` function. See 412 // [the Python documentation](http://docs.python.org/library/functions.html#range). 413 _.range = function(start, stop, step) { 414 if (arguments.length <= 1) { 415 stop = start || 0; 416 start = 0; 417 } 418 step = arguments[2] || 1; 419 420 var len = Math.max(Math.ceil((stop - start) / step), 0); 421 var idx = 0; 422 var range = new Array(len); 423 424 while(idx < len) { 425 range[idx++] = start; 426 start += step; 427 } 428 429 return range; 430 }; 431 432 // Function (ahem) Functions 433 // ------------------ 434 435 // Create a function bound to a given object (assigning `this`, and arguments, 436 // optionally). Binding with arguments is also known as `curry`. 437 // Delegates to **ECMAScript 5**'s native `Function.bind` if available. 438 // We check for `func.bind` first, to fail fast when `func` is undefined. 439 _.bind = function(func, obj) { 440 if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1)); 441 var args = slice.call(arguments, 2); 442 return function() { 443 return func.apply(obj, args.concat(slice.call(arguments))); 444 }; 445 }; 446 447 // Bind all of an object's methods to that object. Useful for ensuring that 448 // all callbacks defined on an object belong to it. 449 _.bindAll = function(obj) { 450 var funcs = slice.call(arguments, 1);
451 if (funcs.length == 0) funcs = _.functions(obj); 452 each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); }); 453 return obj; 454 }; 455 456 // Memoize an expensive function by storing its results. 457 _.memoize = function(func, hasher) { 458 var memo = {}; 459 hasher || (hasher = _.identity); 460 return function() { 461 var key = hasher.apply(this, arguments); 462 return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments)); 463 }; 464 }; 465 466 // Delays a function for the given number of milliseconds, and then calls 467 // it with the arguments supplied. 468 _.delay = function(func, wait) { 469 var args = slice.call(arguments, 2); 470 return setTimeout(function(){ return func.apply(func, args); }, wait); 471 }; 472 473 // Defers a function, scheduling it to run after the current call stack has 474 // cleared. 475 _.defer = function(func) { 476 return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1))); 477 }; 478 479 // Internal function used to implement `_.throttle` and `_.debounce`. 480 var limit = function(func, wait, debounce) { 481 var timeout; 482 return function() { 483 var context = this, args = arguments; 484 var throttler = function() { 485 timeout = null; 486 func.apply(context, args); 487 }; 488 if (debounce) clearTimeout(timeout); 489 if (debounce || !timeout) timeout = setTimeout(throttler, wait); 490 }; 491 }; 492 493 // Returns a function, that, when invoked, will only be triggered at most once 494 // during a given window of time. 495 _.throttle = function(func, wait) { 496 return limit(func, wait, false); 497 }; 498 499 // Returns a function, that, as long as it continues to be invoked, will not 500 // be triggered. The function will be called after it stops being called for 501 // N milliseconds. 502 _.debounce = function(func, wait) { 503 return limit(func, wait, true); 504 }; 505 506 // Returns a function that will be executed at most one time, no matter how 507 // often you call it. Useful for lazy initialization. 508 _.once = function(func) { 509 var ran = false, memo; 510 return function() { 511 if (ran) return memo; 512 ran = true; 513 return memo = func.apply(this, arguments); 514 }; 515 }; 516 517 // Returns the first function passed as an argument to the second, 518 // allowing you to adjust arguments, run code before and after, and 519 // conditionally execute the original function. 520 _.wrap = function(func, wrapper) { 521 return function() { 522 var args = [func].concat(slice.call(arguments)); 523 return wrapper.apply(this, args); 524 }; 525 }; 526 527 // Returns a function that is the composition of a list of functions, each 528 // consuming the return value of the function that follows. 529 _.compose = function() { 530 var funcs = slice.call(arguments); 531 return function() { 532 var args = slice.call(arguments); 533 for (var i = funcs.length - 1; i >= 0; i--) { 534 args = [funcs[i].apply(this, args)]; 535 } 536 return args[0]; 537 }; 538 }; 539 540 // Returns a function that will only be executed after being called N times. 541 _.after = function(times, func) { 542 return function() { 543 if (--times < 1) { return func.apply(this, arguments); } 544 }; 545 }; 546 547 548 // Object Functions 549 // ---------------- 550 551 // Retrieve the names of an object's properties. 552 // Delegates to **ECMAScript 5**'s native `Object.keys` 553 _.keys = nativeKeys || function(obj) { 554 if (obj !== Object(obj)) throw new TypeError('Invalid object'); 555 var keys = []; 556 for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key; 557 return keys; 558 }; 559 560 // Retrieve the values of an object's properties. 561 _.values = function(obj) { 562 return _.map(obj, _.identity); 563 }; 564 565 // Return a sorted list of the function names available on the object. 566 // Aliased as `methods` 567 _.functions = _.methods = function(obj) { 568 var names = []; 569 for (var key in obj) { 570 if (_.isFunction(obj[key])) names.push(key); 571 } 572 return names.sort(); 573 }; 574 575 // Extend a given object with all the properties in passed-in object(s). 576 _.extend = function(obj) { 577 each(slice.call(arguments, 1), function(source) { 578 for (var prop in source) { 579 if (source[prop] !== void 0) obj[prop] = source[prop]; 580 } 581 }); 582 return obj; 583 }; 584 585 // Fill in a given object with default properties. 586 _.defaults = function(obj) { 587 each(slice.call(arguments, 1), function(source) { 588 for (var prop in source) { 589 if (obj[prop] == null) obj[prop] = source[prop]; 590 } 591 }); 592 return obj; 593 }; 594 595 // Create a (shallow-cloned) duplicate of an object. 596 _.clone = function(obj) { 597 return _.isArray(obj) ? obj.slice() : _.extend({}, obj); 598 }; 599 600 // Invokes interceptor with the obj, and then returns obj.
601 // The primary purpose of this method is to "tap into" a method chain, in 602 // order to perform operations on intermediate results within the chain. 603 _.tap = function(obj, interceptor) { 604 interceptor(obj); 605 return obj; 606 }; 607 608 // Perform a deep comparison to check if two objects are equal. 609 _.isEqual = function(a, b) { 610 // Check object identity. 611 if (a === b) return true; 612 // Different types? 613 var atype = typeof(a), btype = typeof(b); 614 if (atype != btype) return false; 615 // Basic equality test (watch out for coercions). 616 if (a == b) return true; 617 // One is falsy and the other truthy. 618 if ((!a && b) || (a && !b)) return false; 619 // Unwrap any wrapped objects. 620 if (a._chain) a = a._wrapped; 621 if (b._chain) b = b._wrapped; 622 // One of them implements an isEqual()? 623 if (a.isEqual) return a.isEqual(b); 624 if (b.isEqual) return b.isEqual(a); 625 // Check dates' integer values. 626 if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime(); 627 // Both are NaN? 628 if (_.isNaN(a) && _.isNaN(b)) return false; 629 // Compare regular expressions. 630 if (_.isRegExp(a) && _.isRegExp(b)) 631 return a.source === b.source && 632 a.global === b.global && 633 a.ignoreCase === b.ignoreCase && 634 a.multiline === b.multiline; 635 // If a is not an object by this point, we can't handle it. 636 if (atype !== 'object') return false; 637 // Check for different array lengths before comparing contents. 638 if (a.length && (a.length !== b.length)) return false; 639 // Nothing else worked, deep compare the contents. 640 var aKeys = _.keys(a), bKeys = _.keys(b); 641 // Different object sizes? 642 if (aKeys.length != bKeys.length) return false;
643 // Recursive comparison of contents. 644 for (var key in a) if (!(key in b) || !_.isEqual(a[key], b[key])) return false; 645 return true; 646 }; 647 648 // Is a given array or object empty? 649 _.isEmpty = function(obj) { 650 if (_.isArray(obj) || _.isString(obj)) return obj.length === 0; 651 for (var key in obj) if (hasOwnProperty.call(obj, key)) return false; 652 return true; 653 }; 654 655 // Is a given value a DOM element? 656 _.isElement = function(obj) { 657 return !!(obj && obj.nodeType == 1); 658 }; 659 660 // Is a given value an array? 661 // Delegates to ECMA5's native Array.isArray 662 _.isArray = nativeIsArray || function(obj) { 663 return toString.call(obj) === '[object Array]'; 664 }; 665 666 // Is a given variable an object? 667 _.isObject = function(obj) { 668 return obj === Object(obj); 669 }; 670 671 // Is a given variable an arguments object? 672 _.isArguments = function(obj) { 673 return !!(obj && hasOwnProperty.call(obj, 'callee')); 674 }; 675 676 // Is a given value a function? 677 _.isFunction = function(obj) { 678 return !!(obj && obj.constructor && obj.call && obj.apply); 679 }; 680 681 // Is a given value a string? 682 _.isString = function(obj) { 683 return !!(obj === '' || (obj && obj.charCodeAt && obj.substr)); 684 }; 685 686 // Is a given value a number? 687 _.isNumber = function(obj) { 688 return !!(obj === 0 || (obj && obj.toExponential && obj.toFixed)); 689 }; 690 691 // Is the given value `NaN`? `NaN` happens to be the only value in JavaScript 692 // that does not equal itself. 693 _.isNaN = function(obj) { 694 return obj !== obj; 695 }; 696 697 // Is a given value a boolean? 698 _.isBoolean = function(obj) { 699 return obj === true || obj === false; 700 }; 701 702 // Is a given value a date? 703 _.isDate = function(obj) { 704 return !!(obj && obj.getTimezoneOffset && obj.setUTCFullYear); 705 }; 706 707 // Is the given value a regular expression? 708 _.isRegExp = function(obj) { 709 return !!(obj && obj.test && obj.exec && (obj.ignoreCase || obj.ignoreCase === false)); 710 }; 711 712 // Is a given value equal to null? 713 _.isNull = function(obj) { 714 return obj === null; 715 }; 716 717 // Is a given variable undefined? 718 _.isUndefined = function(obj) { 719 return obj === void 0; 720 }; 721 722 // Utility Functions 723 // ----------------- 724 725 // Run Underscore.js in *noConflict* mode, returning the `_` variable to its 726 // previous owner. Returns a reference to the Underscore object. 727 _.noConflict = function() { 728 root._ = previousUnderscore; 729 return this; 730 }; 731 732 // Keep the identity function around for default iterators. 733 _.identity = function(value) { 734 return value; 735 }; 736 737 // Run a function **n** times. 738 _.times = function (n, iterator, context) { 739 for (var i = 0; i < n; i++) iterator.call(context, i); 740 }; 741 742 // Add your own custom functions to the Underscore object, ensuring that 743 // they're correctly added to the OOP wrapper as well. 744 _.mixin = function(obj) { 745 each(_.functions(obj), function(name){ 746 addToWrapper(name, _[name] = obj[name]); 747 }); 748 }; 749 750 // Generate a unique integer id (unique within the entire client session). 751 // Useful for temporary DOM ids. 752 var idCounter = 0; 753 _.uniqueId = function(prefix) { 754 var id = idCounter++; 755 return prefix ? prefix + id : id; 756 }; 757 758 // By default, Underscore uses ERB-style template delimiters, change the 759 // following template settings to use alternative delimiters. 760 _.templateSettings = { 761 evaluate : /<%([\s\S]+?)%>/g, 762 interpolate : /<%=([\s\S]+?)%>/g 763 }; 764 765 // JavaScript micro-templating, similar to John Resig's implementation. 766 // Underscore templating handles arbitrary delimiters, preserves whitespace, 767 // and correctly escapes quotes within interpolated code. 768 _.template = function(str, data) { 769 var c = _.templateSettings; 770 var tmpl = 'var __p=[],print=function(){__p.push.apply(__p,arguments);};' + 771 'with(obj||{}){__p.push(\'' + 772 str.replace(/\\/g, '\\\\') 773 .replace(/'/g, "\\'") 774 .replace(c.interpolate, function(match, code) { 775 return "'," + code.replace(/\\'/g, "'") + ",'"; 776 }) 777 .replace(c.evaluate || null, function(match, code) { 778 return "');" + code.replace(/\\'/g, "'") 779 .replace(/[\r\n\t]/g, ' ') + "__p.push('"; 780 }) 781 .replace(/\r/g, '\\r') 782 .replace(/\n/g, '\\n') 783 .replace(/\t/g, '\\t') 784 + "');}return __p.join('');"; 785 var func = new Function('obj', tmpl); 786 return data ? func(data) : func; 787 }; 788 789 // The OOP Wrapper 790 // --------------- 791 792 // If Underscore is called as a function, it returns a wrapped object that 793 // can be used OO-style. This wrapper holds altered versions of all the 794 // underscore functions. Wrapped objects may be chained. 795 var wrapper = function(obj) { this._wrapped = obj; }; 796 797 // Expose `wrapper.prototype` as `_.prototype`
798 _.prototype = wrapper.prototype; 799 800 // Helper function to continue chaining intermediate results. 801 var result = function(obj, chain) { 802 return chain ? _(obj).chain() : obj; 803 }; 804 805 // A method to easily add functions to the OOP wrapper. 806 var addToWrapper = function(name, func) { 807 wrapper.prototype[name] = function() { 808 var args = slice.call(arguments); 809 unshift.call(args, this._wrapped); 810 return result(func.apply(_, args), this._chain); 811 }; 812 }; 813 814 // Add all of the Underscore functions to the wrapper object. 815 _.mixin(_); 816 817 // Add all mutator Array functions to the wrapper. 818 each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) { 819 var method = ArrayProto[name]; 820 wrapper.prototype[name] = function() { 821 method.apply(this._wrapped, arguments); 822 return result(this._wrapped, this._chain); 823 }; 824 }); 825 826 // Add all accessor Array functions to the wrapper. 827 each(['concat', 'join', 'slice'], function(name) { 828 var method = ArrayProto[name]; 829 wrapper.prototype[name] = function() { 830 return result(method.apply(this._wrapped, arguments), this._chain); 831 }; 832 }); 833 834 // Start chaining a wrapped Underscore object. 835 wrapper.prototype.chain = function() { 836 this._chain = true; 837 return this; 838 }; 839 840 // Extracts the result from a wrapped and chained object. 841 wrapper.prototype.value = function() { 842 return this._wrapped; 843 }; 844 845})();
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