1  
   2    # Underscore.coffee
   3    # (c) 2010 Jeremy Ashkenas, DocumentCloud Inc.
   4    # Underscore is freely distributable under the terms of the MIT license.
   5    # Portions of Underscore are inspired by or borrowed from Prototype.js,
   6    # Oliver Steele's Functional, and John Resig's Micro-Templating.
   7    # For all details and documentation:
   8    # http://documentcloud.github.com/underscore/
   9  
  10  
  11    # ------------------------- Baseline setup ---------------------------------
  12  
  13    # Establish the root object, "window" in the browser, or "global" on the server.
  14    root: this
  15  
  16  
  17    # Save the previous value of the "_" variable.
  18    previousUnderscore: root._
  19  
  20  
  21    # Establish the object that gets thrown to break out of a loop iteration.
  22    breaker: if typeof(StopIteration) is 'undefined' then '__break__' else StopIteration
  23  
  24  
  25    # Quick regexp-escaping function, because JS doesn't have RegExp.escape().
  26    escapeRegExp: (string) -> string.replace(/([.*+?^${}()|[\]\/\\])/g, '\\$1')
  27  
  28  
  29    # Save bytes in the minified (but not gzipped) version:
  30    ArrayProto:           Array.prototype
  31    ObjProto:             Object.prototype
  32  
  33  
  34    #Create quick reference variables for speed access to core prototypes.
  35    slice:                ArrayProto.slice
  36    unshift:              ArrayProto.unshift
  37    toString:             ObjProto.toString
  38    hasOwnProperty:       ObjProto.hasOwnProperty
  39    propertyIsEnumerable: ObjProto.propertyIsEnumerable
  40  
  41  
  42    # All ECMA5 native implementations we hope to use are declared here.
  43    nativeForEach:        ArrayProto.forEach
  44    nativeMap:            ArrayProto.map
  45    nativeReduce:         ArrayProto.reduce
  46    nativeReduceRight:    ArrayProto.reduceRight
  47    nativeFilter:         ArrayProto.filter
  48    nativeEvery:          ArrayProto.every
  49    nativeSome:           ArrayProto.some
  50    nativeIndexOf:        ArrayProto.indexOf
  51    nativeLastIndexOf:    ArrayProto.lastIndexOf
  52    nativeIsArray:        Array.isArray
  53    nativeKeys:           Object.keys
  54  
  55  
  56    # Create a safe reference to the Underscore object for use below.
  57    _: (obj) -> new wrapper(obj)
  58  
  59  
  60    # Export the Underscore object for CommonJS.
  61    if typeof(exports) != 'undefined' then exports._: _
  62  
  63  
  64    # Export Underscore to global scope.
  65    root._: _
  66  
  67  
  68    # Current version.
  69    _.VERSION: '0.6.0'
  70  
  71  
  72    # ------------------------ Collection Functions: ---------------------------
  73  
  74    # The cornerstone, an each implementation.
  75    # Handles objects implementing forEach, arrays, and raw objects.
  76    _.each: (obj, iterator, context) ->
  77      try
  78        if nativeForEach and obj.forEach is nativeForEach
  79          obj.forEach iterator, context
  80        else if _.isNumber obj.length
  81          iterator.call(context, obj[i], i, obj) for i in [0...obj.length]
  82        else
  83          iterator.call(context, val, key, obj) for key, val of obj
  84      catch e
  85        throw e if e isnt breaker
  86      obj
  87  
  88  
  89    # Return the results of applying the iterator to each element. Use JavaScript
  90    # 1.6's version of map, if possible.
  91    _.map: (obj, iterator, context) ->
  92      return obj.map(iterator, context) if nativeMap and obj.map is nativeMap
  93      results: []
  94      _.each obj, (value, index, list) ->
  95        results.push iterator.call context, value, index, list
  96      results
  97  
  98  
  99    # Reduce builds up a single result from a list of values. Also known as
 100    # inject, or foldl. Uses JavaScript 1.8's version of reduce, if possible.
 101    _.reduce: (obj, memo, iterator, context) ->
 102      return obj.reduce(_.bind(iterator, context), memo) if nativeReduce and obj.reduce is nativeReduce
 103      _.each obj, (value, index, list) ->
 104        memo: iterator.call context, memo, value, index, list
 105      memo
 106  
 107  
 108    # The right-associative version of reduce, also known as foldr. Uses
 109    # JavaScript 1.8's version of reduceRight, if available.
 110    _.reduceRight: (obj, memo, iterator, context) ->
 111      return obj.reduceRight(_.bind(iterator, context), memo) if nativeReduceRight and obj.reduceRight is nativeReduceRight
 112      _.each _.clone(_.toArray(obj)).reverse(), (value, index) ->
 113        memo: iterator.call context, memo, value, index, obj
 114      memo
 115  
 116  
 117    # Return the first value which passes a truth test.
 118    _.detect: (obj, iterator, context) ->
 119      result: null
 120      _.each obj, (value, index, list) ->
 121        if iterator.call context, value, index, list
 122          result: value
 123          _.breakLoop()
 124      result
 125  
 126  
 127    # Return all the elements that pass a truth test. Use JavaScript 1.6's
 128    # filter(), if it exists.
 129    _.filter: (obj, iterator, context) ->
 130      return obj.filter iterator, context if nativeFilter and obj.filter is nativeFilter
 131      results: []
 132      _.each obj, (value, index, list) ->
 133        results.push value if iterator.call context, value, index, list
 134      results
 135  
 136  
 137    # Return all the elements for which a truth test fails.
 138    _.reject: (obj, iterator, context) ->
 139      results: []
 140      _.each obj, (value, index, list) ->
 141        results.push value if not iterator.call context, value, index, list
 142      results
 143  
 144  
 145    # Determine whether all of the elements match a truth test. Delegate to
 146    # JavaScript 1.6's every(), if it is present.
 147    _.every: (obj, iterator, context) ->
 148      iterator ||= _.identity
 149      return obj.every iterator, context if nativeEvery and obj.every is nativeEvery
 150      result: true
 151      _.each obj, (value, index, list) ->
 152        _.breakLoop() unless (result: result and iterator.call(context, value, index, list))
 153      result
 154  
 155  
 156    # Determine if at least one element in the object matches a truth test. Use
 157    # JavaScript 1.6's some(), if it exists.
 158    _.some: (obj, iterator, context) ->
 159      iterator ||= _.identity
 160      return obj.some iterator, context if nativeSome and obj.some is nativeSome
 161      result: false
 162      _.each obj, (value, index, list) ->
 163        _.breakLoop() if (result: iterator.call(context, value, index, list))
 164      result
 165  
 166  
 167    # Determine if a given value is included in the array or object,
 168    # based on '==='.
 169    _.include: (obj, target) ->
 170      return _.indexOf(obj, target) isnt -1 if nativeIndexOf and obj.indexOf is nativeIndexOf
 171      for key, val of obj
 172        return true if val is target
 173      false
 174  
 175  
 176    # Invoke a method with arguments on every item in a collection.
 177    _.invoke: (obj, method) ->
 178      args: _.rest arguments, 2
 179      (if method then val[method] else val).apply(val, args) for val in obj
 180  
 181  
 182    # Convenience version of a common use case of map: fetching a property.
 183    _.pluck: (obj, key) ->
 184      _.map(obj, (val) -> val[key])
 185  
 186  
 187    # Return the maximum item or (item-based computation).
 188    _.max: (obj, iterator, context) ->
 189      return Math.max.apply(Math, obj) if not iterator and _.isArray(obj)
 190      result: {computed: -Infinity}
 191      _.each obj, (value, index, list) ->
 192        computed: if iterator then iterator.call(context, value, index, list) else value
 193        computed >= result.computed and (result: {value: value, computed: computed})
 194      result.value
 195  
 196  
 197    # Return the minimum element (or element-based computation).
 198    _.min: (obj, iterator, context) ->
 199      return Math.min.apply(Math, obj) if not iterator and _.isArray(obj)
 200      result: {computed: Infinity}
 201      _.each obj, (value, index, list) ->
 202        computed: if iterator then iterator.call(context, value, index, list) else value
 203        computed < result.computed and (result: {value: value, computed: computed})
 204      result.value
 205  
 206  
 207    # Sort the object's values by a criterion produced by an iterator.
 208    _.sortBy: (obj, iterator, context) ->
 209      _.pluck(((_.map obj, (value, index, list) ->
 210        {value: value, criteria: iterator.call(context, value, index, list)}
 211      ).sort((left, right) ->
 212        a: left.criteria; b: right.criteria
 213        if a < b then -1 else if a > b then 1 else 0
 214      )), 'value')
 215  
 216  
 217    # Use a comparator function to figure out at what index an object should
 218    # be inserted so as to maintain order. Uses binary search.
 219    _.sortedIndex: (array, obj, iterator) ->
 220      iterator ||= _.identity
 221      low:  0
 222      high: array.length
 223      while low < high
 224        mid: (low + high) >> 1
 225        if iterator(array[mid]) < iterator(obj) then low: mid + 1 else high: mid
 226      low
 227  
 228  
 229    # Convert anything iterable into a real, live array.
 230    _.toArray: (iterable) ->
 231      return []                   if (!iterable)
 232      return iterable.toArray()   if (iterable.toArray)
 233      return iterable             if (_.isArray(iterable))
 234      return slice.call(iterable) if (_.isArguments(iterable))
 235      _.values(iterable)
 236  
 237  
 238    # Return the number of elements in an object.
 239    _.size: (obj) -> _.toArray(obj).length
 240  
 241  
 242    # -------------------------- Array Functions: ------------------------------
 243  
 244    # Get the first element of an array. Passing "n" will return the first N
 245    # values in the array. Aliased as "head". The "guard" check allows it to work
 246    # with _.map.
 247    _.first: (array, n, guard) ->
 248      if n and not guard then slice.call(array, 0, n) else array[0]
 249  
 250  
 251    # Returns everything but the first entry of the array. Aliased as "tail".
 252    # Especially useful on the arguments object. Passing an "index" will return
 253    # the rest of the values in the array from that index onward. The "guard"
 254    # check allows it to work with _.map.
 255    _.rest: (array, index, guard) ->
 256      slice.call(array, if _.isUndefined(index) or guard then 1 else index)
 257  
 258  
 259    # Get the last element of an array.
 260    _.last: (array) -> array[array.length - 1]
 261  
 262  
 263    # Trim out all falsy values from an array.
 264    _.compact: (array) -> item for item in array when item
 265  
 266  
 267    # Return a completely flattened version of an array.
 268    _.flatten: (array) ->
 269      _.reduce array, [], (memo, value) ->
 270        return memo.concat(_.flatten(value)) if _.isArray value
 271        memo.push value
 272        memo
 273  
 274  
 275    # Return a version of the array that does not contain the specified value(s).
 276    _.without: (array) ->
 277      values: _.rest arguments
 278      val for val in _.toArray(array) when not _.include values, val
 279  
 280  
 281    # Produce a duplicate-free version of the array. If the array has already
 282    # been sorted, you have the option of using a faster algorithm.
 283    _.uniq: (array, isSorted) ->
 284      memo: []
 285      for el, i in _.toArray array
 286        memo.push el if i is 0 || (if isSorted is true then _.last(memo) isnt el else not _.include(memo, el))
 287      memo
 288  
 289  
 290    # Produce an array that contains every item shared between all the
 291    # passed-in arrays.
 292    _.intersect: (array) ->
 293      rest: _.rest arguments
 294      _.select _.uniq(array), (item) ->
 295        _.all rest, (other) ->
 296          _.indexOf(other, item) >= 0
 297  
 298  
 299    # Zip together multiple lists into a single array -- elements that share
 300    # an index go together.
 301    _.zip: ->
 302      length:  _.max _.pluck arguments, 'length'
 303      results: new Array length
 304      for i in [0...length]
 305        results[i]: _.pluck arguments, String i
 306      results
 307  
 308  
 309    # If the browser doesn't supply us with indexOf (I'm looking at you, MSIE),
 310    # we need this function. Return the position of the first occurence of an
 311    # item in an array, or -1 if the item is not included in the array.
 312    _.indexOf: (array, item) ->
 313      return array.indexOf item if nativeIndexOf and array.indexOf is nativeIndexOf
 314      i: 0; l: array.length
 315      while l - i
 316        if array[i] is item then return i else i++
 317      -1
 318  
 319  
 320    # Provide JavaScript 1.6's lastIndexOf, delegating to the native function,
 321    # if possible.
 322    _.lastIndexOf: (array, item) ->
 323      return array.lastIndexOf(item) if nativeLastIndexOf and array.lastIndexOf is nativeLastIndexOf
 324      i: array.length
 325      while i
 326        if array[i] is item then return i else i--
 327      -1
 328  
 329  
 330    # Generate an integer Array containing an arithmetic progression. A port of
 331    # the native Python range() function. See:
 332    # http://docs.python.org/library/functions.html#range
 333    _.range: (start, stop, step) ->
 334      a:        arguments
 335      solo:     a.length <= 1
 336      i: start: if solo then 0 else a[0]
 337      stop:     if solo then a[0] else a[1]
 338      step:     a[2] or 1
 339      len:      Math.ceil((stop - start) / step)
 340      return [] if len <= 0
 341      range:    new Array len
 342      idx:      0
 343      while true
 344        return range if (if step > 0 then i - stop else stop - i) >= 0
 345        range[idx]: i
 346        idx++
 347        i+= step
 348  
 349  
 350    # ----------------------- Function Functions: -----------------------------
 351  
 352    # Create a function bound to a given object (assigning 'this', and arguments,
 353    # optionally). Binding with arguments is also known as 'curry'.
 354    _.bind: (func, obj) ->
 355      args: _.rest arguments, 2
 356      -> func.apply obj or root, args.concat arguments
 357  
 358  
 359    # Bind all of an object's methods to that object. Useful for ensuring that
 360    # all callbacks defined on an object belong to it.
 361    _.bindAll: (obj) ->
 362      funcs: if arguments.length > 1 then _.rest(arguments) else _.functions(obj)
 363      _.each funcs, (f) -> obj[f]: _.bind obj[f], obj
 364      obj
 365  
 366  
 367    # Delays a function for the given number of milliseconds, and then calls
 368    # it with the arguments supplied.
 369    _.delay: (func, wait) ->
 370      args: _.rest arguments, 2
 371      setTimeout((-> func.apply(func, args)), wait)
 372  
 373  
 374    # Defers a function, scheduling it to run after the current call stack has
 375    # cleared.
 376    _.defer: (func) ->
 377      _.delay.apply _, [func, 1].concat _.rest arguments
 378  
 379  
 380    # Returns the first function passed as an argument to the second,
 381    # allowing you to adjust arguments, run code before and after, and
 382    # conditionally execute the original function.
 383    _.wrap: (func, wrapper) ->
 384      -> wrapper.apply wrapper, [func].concat arguments
 385  
 386  
 387    # Returns a function that is the composition of a list of functions, each
 388    # consuming the return value of the function that follows.
 389    _.compose: ->
 390      funcs: arguments
 391      ->
 392        args: arguments
 393        for i in [(funcs.length - 1)..0]
 394          args: [funcs[i].apply(this, args)]
 395        args[0]
 396  
 397  
 398    # ------------------------- Object Functions: ----------------------------
 399  
 400    # Retrieve the names of an object's properties.
 401    _.keys: nativeKeys or (obj) ->
 402      return _.range 0, obj.length if _.isArray(obj)
 403      key for key, val of obj
 404  
 405  
 406    # Retrieve the values of an object's properties.
 407    _.values: (obj) ->
 408      _.map obj, _.identity
 409  
 410  
 411    # Return a sorted list of the function names available in Underscore.
 412    _.functions: (obj) ->
 413      _.filter(_.keys(obj), (key) -> _.isFunction(obj[key])).sort()
 414  
 415  
 416    # Extend a given object with all of the properties in a source object.
 417    _.extend: (destination, source) ->
 418      (destination[key]: val) for key, val of source
 419      destination
 420  
 421  
 422    # Create a (shallow-cloned) duplicate of an object.
 423    _.clone: (obj) ->
 424      return obj.slice 0 if _.isArray obj
 425      _.extend {}, obj
 426  
 427  
 428    # Invokes interceptor with the obj, and then returns obj.
 429    # The primary purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.
 430    _.tap: (obj, interceptor) ->
 431      interceptor obj
 432      obj
 433  
 434  
 435    # Perform a deep comparison to check if two objects are equal.
 436    _.isEqual: (a, b) ->
 437      # Check object identity.
 438      return true if a is b
 439      # Different types?
 440      atype: typeof(a); btype: typeof(b)
 441      return false if atype isnt btype
 442      # Basic equality test (watch out for coercions).
 443      return true if `a == b`
 444      # One is falsy and the other truthy.
 445      return false if (!a and b) or (a and !b)
 446      # One of them implements an isEqual()?
 447      return a.isEqual(b) if a.isEqual
 448      # Check dates' integer values.
 449      return a.getTime() is b.getTime() if _.isDate(a) and _.isDate(b)
 450      # Both are NaN?
 451      return true if _.isNaN(a) and _.isNaN(b)
 452      # Compare regular expressions.
 453      if _.isRegExp(a) and _.isRegExp(b)
 454        return a.source     is b.source and
 455               a.global     is b.global and
 456               a.ignoreCase is b.ignoreCase and
 457               a.multiline  is b.multiline
 458      # If a is not an object by this point, we can't handle it.
 459      return false if atype isnt 'object'
 460      # Check for different array lengths before comparing contents.
 461      return false if a.length and (a.length isnt b.length)
 462      # Nothing else worked, deep compare the contents.
 463      aKeys: _.keys(a); bKeys: _.keys(b)
 464      # Different object sizes?
 465      return false if aKeys.length isnt bKeys.length
 466      # Recursive comparison of contents.
 467      (return false) for key, val of a when !_.isEqual(val, b[key])
 468      true
 469  
 470  
 471    # Is a given array or object empty?
 472    _.isEmpty: (obj) ->
 473      return obj.length is 0 if _.isArray obj
 474      (return false) for key of obj when hasOwnProperty.call(obj, key)
 475      true
 476  
 477  
 478    # Is a given value a DOM element?
 479    _.isElement:    (obj) -> obj and obj.nodeType is 1
 480  
 481  
 482    # Is a given value an array?
 483    _.isArray:      nativeIsArray or (obj) -> !!(obj and obj.concat and obj.unshift)
 484  
 485  
 486    # Is a given variable an arguments object?
 487    _.isArguments:  (obj) -> obj and _.isNumber(obj.length) and not obj.concat and
 488                             not obj.substr and not obj.apply and not propertyIsEnumerable.call(obj, 'length')
 489  
 490  
 491    # Is the given value a function?
 492    _.isFunction:   (obj) -> !!(obj and obj.constructor and obj.call and obj.apply)
 493  
 494  
 495    # Is the given value a string?
 496    _.isString:     (obj) -> !!(obj is '' or (obj and obj.charCodeAt and obj.substr))
 497  
 498  
 499    # Is a given value a number?
 500    _.isNumber:     (obj) -> (obj is +obj) or toString.call(obj) is '[object Number]'
 501  
 502  
 503    # Is a given value a boolean?
 504    _.isBoolean:    (obj) -> obj is true or obj is false
 505  
 506  
 507    # Is a given value a Date?
 508    _.isDate:       (obj) -> !!(obj and obj.getTimezoneOffset and obj.setUTCFullYear)
 509  
 510  
 511    # Is the given value a regular expression?
 512    _.isRegExp:     (obj) -> !!(obj and obj.exec and (obj.ignoreCase or obj.ignoreCase is false))
 513  
 514  
 515    # Is the given value NaN -- this one is interesting. NaN != NaN, and
 516    # isNaN(undefined) == true, so we make sure it's a number first.
 517    _.isNaN:        (obj) -> _.isNumber(obj) and window.isNaN(obj)
 518  
 519  
 520    # Is a given value equal to null?
 521    _.isNull:       (obj) -> obj is null
 522  
 523  
 524    # Is a given variable undefined?
 525    _.isUndefined:  (obj) -> typeof obj is 'undefined'
 526  
 527  
 528    # -------------------------- Utility Functions: --------------------------
 529  
 530    # Run Underscore.js in noConflict mode, returning the '_' variable to its
 531    # previous owner. Returns a reference to the Underscore object.
 532    _.noConflict: ->
 533      root._: previousUnderscore
 534      this
 535  
 536  
 537    # Keep the identity function around for default iterators.
 538    _.identity: (value) -> value
 539  
 540  
 541    # Run a function n times.
 542    _.times: (n, iterator, context) ->
 543      iterator.call(context, i) for i in [0...n]
 544  
 545  
 546    # Break out of the middle of an iteration.
 547    _.breakLoop: -> throw breaker
 548  
 549  
 550    # Add your own custom functions to the Underscore object, ensuring that
 551    # they're correctly added to the OOP wrapper as well.
 552    _.mixin: (obj) ->
 553      for name in _.functions(obj)
 554        addToWrapper name, _[name]: obj[name]
 555  
 556  
 557    # Generate a unique integer id (unique within the entire client session).
 558    # Useful for temporary DOM ids.
 559    idCounter: 0
 560    _.uniqueId: (prefix) ->
 561      (prefix or '') + idCounter++
 562  
 563  
 564    # By default, Underscore uses ERB-style template delimiters, change the
 565    # following template settings to use alternative delimiters.
 566    _.templateSettings: {
 567      start:        '<%'
 568      end:          '%>'
 569      interpolate:  /<%=(.+?)%>/g
 570    }
 571  
 572  
 573    # JavaScript templating a-la ERB, pilfered from John Resig's
 574    # "Secrets of the JavaScript Ninja", page 83.
 575    # Single-quote fix from Rick Strahl's version.
 576    _.template: (str, data) ->
 577      c: _.templateSettings
 578      endMatch: new RegExp("'(?=[^"+c.end.substr(0, 1)+"]*"+escapeRegExp(c.end)+")","g")
 579      fn: new Function 'obj',
 580        'var p=[],print=function(){p.push.apply(p,arguments);};' +
 581        'with(obj){p.push(\'' +
 582        str.replace(/[\r\t\n]/g, " ")
 583           .replace(endMatch,"\t")
 584           .split("'").join("\\'")
 585           .split("\t").join("'")
 586           .replace(c.interpolate, "',$1,'")
 587           .split(c.start).join("');")
 588           .split(c.end).join("p.push('") +
 589           "');}return p.join('');"
 590      if data then fn(data) else fn
 591  
 592  
 593    # ------------------------------- Aliases ----------------------------------
 594  
 595    _.forEach: _.each
 596    _.foldl:   _.inject:      _.reduce
 597    _.foldr:   _.reduceRight
 598    _.select:  _.filter
 599    _.all:     _.every
 600    _.any:     _.some
 601    _.head:    _.first
 602    _.tail:    _.rest
 603    _.methods: _.functions
 604  
 605  
 606    # ------------------------ Setup the OOP Wrapper: --------------------------
 607  
 608    # If Underscore is called as a function, it returns a wrapped object that
 609    # can be used OO-style. This wrapper holds altered versions of all the
 610    # underscore functions. Wrapped objects may be chained.
 611    wrapper: (obj) ->
 612      this._wrapped: obj
 613      this
 614  
 615  
 616    # Helper function to continue chaining intermediate results.
 617    result: (obj, chain) ->
 618      if chain then _(obj).chain() else obj
 619  
 620  
 621    # A method to easily add functions to the OOP wrapper.
 622    addToWrapper: (name, func) ->
 623      wrapper.prototype[name]: ->
 624        args: _.toArray arguments
 625        unshift.call args, this._wrapped
 626        result func.apply(_, args), this._chain
 627  
 628  
 629    # Add all of the Underscore functions to the wrapper object.
 630    _.mixin _
 631  
 632  
 633    # Add all mutator Array functions to the wrapper.
 634    _.each ['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], (name) ->
 635      method: Array.prototype[name]
 636      wrapper.prototype[name]: ->
 637        method.apply(this._wrapped, arguments)
 638        result(this._wrapped, this._chain)
 639  
 640  
 641    # Add all accessor Array functions to the wrapper.
 642    _.each ['concat', 'join', 'slice'], (name) ->
 643      method: Array.prototype[name]
 644      wrapper.prototype[name]: ->
 645        result(method.apply(this._wrapped, arguments), this._chain)
 646  
 647  
 648    # Start chaining a wrapped Underscore object.
 649    wrapper::chain: ->
 650      this._chain: true
 651      this
 652  
 653  
 654    # Extracts the result from a wrapped and chained object.
 655    wrapper::value: -> this._wrapped