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# **
# (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.**
# Underscore is freely distributable under the terms of the
# [MIT license](
# Portions of Underscore are inspired by or borrowed from
# [Prototype.js](, Oliver Steele's
# [Functional](, and John Resig's
# [Micro-Templating](
# For all details and documentation:
# Baseline setup
# --------------
# Establish the root object, `window` in the browser, or `global` on the server.
root = this
# Save the previous value of the `_` variable.
previousUnderscore = root._
# Establish the object that gets thrown to break out of a loop iteration.
# `StopIteration` is SOP on Mozilla.
breaker = if typeof(StopIteration) is 'undefined' then '__break__' else StopIteration
# Helper function to escape **RegExp** contents, because JS doesn't have one.
escapeRegExp = (string) -> string.replace(/([.*+?^${}()|[\]\/\\])/g, '\\$1')
# Save bytes in the minified (but not gzipped) version:
ArrayProto = Array.prototype
ObjProto = Object.prototype
# Create quick reference variables for speed access to core prototypes.
slice = ArrayProto.slice
unshift = ArrayProto.unshift
toString = ObjProto.toString
hasOwnProperty = ObjProto.hasOwnProperty
propertyIsEnumerable = ObjProto.propertyIsEnumerable
# All **ECMA5** native implementations we hope to use are declared here.
nativeForEach = ArrayProto.forEach
nativeMap =
nativeReduce = ArrayProto.reduce
nativeReduceRight = ArrayProto.reduceRight
nativeFilter = ArrayProto.filter
nativeEvery = ArrayProto.every
nativeSome = ArrayProto.some
nativeIndexOf = ArrayProto.indexOf
nativeLastIndexOf = ArrayProto.lastIndexOf
nativeIsArray = Array.isArray
nativeKeys = Object.keys
# Create a safe reference to the Underscore object for use below.
_ = (obj) -> new wrapper(obj)
# Export the Underscore object for **CommonJS**.
if typeof(exports) != 'undefined' then exports._ = _
# Export Underscore to global scope.
root._ = _
# Current version.
_.VERSION = '1.1.0'
# Collection Functions
# --------------------
# The cornerstone, an **each** implementation.
# Handles objects implementing **forEach**, arrays, and raw objects.
_.each = (obj, iterator, context) ->
if nativeForEach and obj.forEach is nativeForEach
obj.forEach iterator, context
else if _.isNumber obj.length context, obj[i], i, obj for i in [0...obj.length]
else context, val, key, obj for own key, val of obj
catch e
throw e if e isnt breaker
# Return the results of applying the iterator to each element. Use JavaScript
# 1.6's version of **map**, if possible. = (obj, iterator, context) ->
return, context) if nativeMap and is nativeMap
results = []
_.each obj, (value, index, list) ->
results.push context, value, index, list
# **Reduce** builds up a single result from a list of values. Also known as
# **inject**, or **foldl**. Uses JavaScript 1.8's version of **reduce**, if possible.
_.reduce = (obj, iterator, memo, context) ->
if nativeReduce and obj.reduce is nativeReduce
iterator = _.bind iterator, context if context
return obj.reduce iterator, memo
_.each obj, (value, index, list) ->
memo = context, memo, value, index, list
# The right-associative version of **reduce**, also known as **foldr**. Uses
# JavaScript 1.8's version of **reduceRight**, if available.
_.reduceRight = (obj, iterator, memo, context) ->
if nativeReduceRight and obj.reduceRight is nativeReduceRight
iterator = _.bind iterator, context if context
return obj.reduceRight iterator, memo
reversed = _.clone(_.toArray(obj)).reverse()
_.reduce reversed, iterator, memo, context
# Return the first value which passes a truth test.
_.detect = (obj, iterator, context) ->
result = null
_.each obj, (value, index, list) ->
if context, value, index, list
result = value
# Return all the elements that pass a truth test. Use JavaScript 1.6's
# **filter**, if it exists.
_.filter = (obj, iterator, context) ->
return obj.filter iterator, context if nativeFilter and obj.filter is nativeFilter
results = []
_.each obj, (value, index, list) ->
results.push value if context, value, index, list
# Return all the elements for which a truth test fails.
_.reject = (obj, iterator, context) ->
results = []
_.each obj, (value, index, list) ->
results.push value if not context, value, index, list
# Determine whether all of the elements match a truth test. Delegate to
# JavaScript 1.6's **every**, if it is present.
_.every = (obj, iterator, context) ->
iterator ||= _.identity
return obj.every iterator, context if nativeEvery and obj.every is nativeEvery
result = true
_.each obj, (value, index, list) ->
_.breakLoop() unless (result = result and, value, index, list))
# Determine if at least one element in the object matches a truth test. Use
# JavaScript 1.6's **some**, if it exists.
_.some = (obj, iterator, context) ->
iterator ||= _.identity
return obj.some iterator, context if nativeSome and obj.some is nativeSome
result = false
_.each obj, (value, index, list) ->
_.breakLoop() if (result =, value, index, list))
# Determine if a given value is included in the array or object,
# based on `===`.
_.include = (obj, target) ->
return _.indexOf(obj, target) isnt -1 if nativeIndexOf and obj.indexOf is nativeIndexOf
return true for own key, val of obj when val is target
# Invoke a method with arguments on every item in a collection.
_.invoke = (obj, method) ->
args = arguments, 2
(if method then val[method] else val).apply(val, args) for val in obj
# Convenience version of a common use case of **map**: fetching a property.
_.pluck = (obj, key) ->, (val) -> val[key])
# Return the maximum item or (item-based computation).
_.max = (obj, iterator, context) ->
return Math.max.apply(Math, obj) if not iterator and _.isArray(obj)
result = computed: -Infinity
_.each obj, (value, index, list) ->
computed = if iterator then, value, index, list) else value
computed >= result.computed and (result = {value: value, computed: computed})
# Return the minimum element (or element-based computation).
_.min = (obj, iterator, context) ->
return Math.min.apply(Math, obj) if not iterator and _.isArray(obj)
result = computed: Infinity
_.each obj, (value, index, list) ->
computed = if iterator then, value, index, list) else value
computed < result.computed and (result = {value: value, computed: computed})
# Sort the object's values by a criterion produced by an iterator.
_.sortBy = (obj, iterator, context) ->
_.pluck((( obj, (value, index, list) ->
{value: value, criteria:, value, index, list)}
).sort((left, right) ->
a = left.criteria; b = right.criteria
if a < b then -1 else if a > b then 1 else 0
)), 'value')
# Use a comparator function to figure out at what index an object should
# be inserted so as to maintain order. Uses binary search.
_.sortedIndex = (array, obj, iterator) ->
iterator ||= _.identity
low = 0
high = array.length
while low < high
mid = (low + high) >> 1
if iterator(array[mid]) < iterator(obj) then low = mid + 1 else high = mid
# Convert anything iterable into a real, live array.
_.toArray = (iterable) ->
return [] if (!iterable)
return iterable.toArray() if (iterable.toArray)
return iterable if (_.isArray(iterable))
return if (_.isArguments(iterable))
# Return the number of elements in an object.
_.size = (obj) -> _.toArray(obj).length
# Array Functions
# ---------------
# Get the first element of an array. Passing `n` will return the first N
# values in the array. Aliased as **head**. The `guard` check allows it to work
# with **map**.
_.first = (array, n, guard) ->
if n and not guard then, 0, n) else array[0]
# Returns everything but the first entry of the array. Aliased as **tail**.
# Especially useful on the arguments object. Passing an `index` will return
# the rest of the values in the array from that index onward. The `guard`
# check allows it to work with **map**. = (array, index, guard) ->, if _.isUndefined(index) or guard then 1 else index)
# Get the last element of an array.
_.last = (array) -> array[array.length - 1]
# Trim out all falsy values from an array.
_.compact = (array) -> item for item in array when item
# Return a completely flattened version of an array.
_.flatten = (array) ->
_.reduce array, (memo, value) ->
return memo.concat(_.flatten(value)) if _.isArray value
memo.push value
, []
# Return a version of the array that does not contain the specified value(s).
_.without = (array) ->
values = arguments
val for val in _.toArray(array) when not _.include values, val
# Produce a duplicate-free version of the array. If the array has already
# been sorted, you have the option of using a faster algorithm.
_.uniq = (array, isSorted) ->
memo = []
for el, i in _.toArray array
memo.push el if i is 0 || (if isSorted is true then _.last(memo) isnt el else not _.include(memo, el))
# Produce an array that contains every item shared between all the
# passed-in arrays.
_.intersect = (array) ->
rest = arguments _.uniq(array), (item) ->
_.all rest, (other) ->
_.indexOf(other, item) >= 0
# Zip together multiple lists into a single array -- elements that share
# an index go together. = ->
length = _.max _.pluck arguments, 'length'
results = new Array length
for i in [0...length]
results[i] = _.pluck arguments, String i
# If the browser doesn't supply us with **indexOf** (I'm looking at you, MSIE),
# we need this function. Return the position of the first occurrence of an
# item in an array, or -1 if the item is not included in the array.
_.indexOf = (array, item) ->
return array.indexOf item if nativeIndexOf and array.indexOf is nativeIndexOf
i = 0; l = array.length
while l - i
if array[i] is item then return i else i++
# Provide JavaScript 1.6's **lastIndexOf**, delegating to the native function,
# if possible.
_.lastIndexOf = (array, item) ->
return array.lastIndexOf(item) if nativeLastIndexOf and array.lastIndexOf is nativeLastIndexOf
i = array.length
while i
if array[i] is item then return i else i--
# Generate an integer Array containing an arithmetic progression. A port of
# [the native Python **range** function](
_.range = (start, stop, step) ->
a = arguments
solo = a.length <= 1
i = start = if solo then 0 else a[0]
stop = if solo then a[0] else a[1]
step = a[2] or 1
len = Math.ceil((stop - start) / step)
return [] if len <= 0
range = new Array len
idx = 0
return range if (if step > 0 then i - stop else stop - i) >= 0
range[idx] = i
i+= step
# Function Functions
# ------------------
# Create a function bound to a given object (assigning `this`, and arguments,
# optionally). Binding with arguments is also known as **curry**.
_.bind = (func, obj) ->
args = arguments, 2
-> func.apply obj or root, args.concat arguments
# Bind all of an object's methods to that object. Useful for ensuring that
# all callbacks defined on an object belong to it.
_.bindAll = (obj) ->
funcs = if arguments.length > 1 then else _.functions(obj)
_.each funcs, (f) -> obj[f] = _.bind obj[f], obj
# Delays a function for the given number of milliseconds, and then calls
# it with the arguments supplied.
_.delay = (func, wait) ->
args = arguments, 2
setTimeout((-> func.apply(func, args)), wait)
# Memoize an expensive function by storing its results.
_.memoize = (func, hasher) ->
memo = {}
hasher or= _.identity
key = hasher.apply this, arguments
return memo[key] if key of memo
memo[key] = func.apply this, arguments
# Defers a function, scheduling it to run after the current call stack has
# cleared.
_.defer = (func) ->
_.delay.apply _, [func, 1].concat arguments
# Returns the first function passed as an argument to the second,
# allowing you to adjust arguments, run code before and after, and
# conditionally execute the original function.
_.wrap = (func, wrapper) ->
-> wrapper.apply wrapper, [func].concat arguments
# Returns a function that is the composition of a list of functions, each
# consuming the return value of the function that follows.
_.compose = ->
funcs = arguments
args = arguments
for i in [funcs.length - 1..0] by -1
args = [funcs[i].apply(this, args)]
# Object Functions
# ----------------
# Retrieve the names of an object's properties.
_.keys = nativeKeys or (obj) ->
return _.range 0, obj.length if _.isArray(obj)
key for key, val of obj
# Retrieve the values of an object's properties.
_.values = (obj) -> obj, _.identity
# Return a sorted list of the function names available in Underscore.
_.functions = (obj) ->
_.filter(_.keys(obj), (key) -> _.isFunction(obj[key])).sort()
# Extend a given object with all of the properties in a source object.
_.extend = (obj) ->
for source in
obj[key] = val for key, val of source
# Create a (shallow-cloned) duplicate of an object.
_.clone = (obj) ->
return obj.slice 0 if _.isArray obj
_.extend {}, obj
# Invokes interceptor with the obj, and then returns obj.
# The primary purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.
_.tap = (obj, interceptor) ->
interceptor obj
# Perform a deep comparison to check if two objects are equal.
_.isEqual = (a, b) ->
# Check object identity.
return true if a is b
# Different types?
atype = typeof(a); btype = typeof(b)
return false if atype isnt btype
# Basic equality test (watch out for coercions).
return true if `a == b`
# One is falsy and the other truthy.
return false if (!a and b) or (a and !b)
# One of them implements an `isEqual()`?
return a.isEqual(b) if a.isEqual
# Check dates' integer values.
return a.getTime() is b.getTime() if _.isDate(a) and _.isDate(b)
# Both are NaN?
return false if _.isNaN(a) and _.isNaN(b)
# Compare regular expressions.
if _.isRegExp(a) and _.isRegExp(b)
return a.source is b.source and is and
a.ignoreCase is b.ignoreCase and
a.multiline is b.multiline
# If a is not an object by this point, we can't handle it.
return false if atype isnt 'object'
# Check for different array lengths before comparing contents.
return false if a.length and (a.length isnt b.length)
# Nothing else worked, deep compare the contents.
aKeys = _.keys(a); bKeys = _.keys(b)
# Different object sizes?
return false if aKeys.length isnt bKeys.length
# Recursive comparison of contents.
return false for key, val of a when !(key of b) or !_.isEqual(val, b[key])
# Is a given array or object empty?
_.isEmpty = (obj) ->
return obj.length is 0 if _.isArray(obj) or _.isString(obj)
return false for own key of obj
# Is a given value a DOM element?
_.isElement = (obj) -> obj and obj.nodeType is 1
# Is a given value an array?
_.isArray = nativeIsArray or (obj) -> !!(obj and obj.concat and obj.unshift and not obj.callee)
# Is a given variable an arguments object?
_.isArguments = (obj) -> obj and obj.callee
# Is the given value a function?
_.isFunction = (obj) -> !!(obj and obj.constructor and and obj.apply)
# Is the given value a string?
_.isString = (obj) -> !!(obj is '' or (obj and obj.charCodeAt and obj.substr))
# Is a given value a number?
_.isNumber = (obj) -> (obj is +obj) or is '[object Number]'
# Is a given value a boolean?
_.isBoolean = (obj) -> obj is true or obj is false
# Is a given value a Date?
_.isDate = (obj) -> !!(obj and obj.getTimezoneOffset and obj.setUTCFullYear)
# Is the given value a regular expression?
_.isRegExp = (obj) -> !!(obj and obj.exec and (obj.ignoreCase or obj.ignoreCase is false))
# Is the given value NaN -- this one is interesting. `NaN != NaN`, and
# `isNaN(undefined) == true`, so we make sure it's a number first.
_.isNaN = (obj) -> _.isNumber(obj) and window.isNaN(obj)
# Is a given value equal to null?
_.isNull = (obj) -> obj is null
# Is a given variable undefined?
_.isUndefined = (obj) -> typeof obj is 'undefined'
# Utility Functions
# -----------------
# Run Underscore.js in noConflict mode, returning the `_` variable to its
# previous owner. Returns a reference to the Underscore object.
_.noConflict = ->
root._ = previousUnderscore
# Keep the identity function around for default iterators.
_.identity = (value) -> value
# Run a function `n` times.
_.times = (n, iterator, context) -> context, i for i in [0...n]
# Break out of the middle of an iteration.
_.breakLoop = -> throw breaker
# Add your own custom functions to the Underscore object, ensuring that
# they're correctly added to the OOP wrapper as well.
_.mixin = (obj) ->
for name in _.functions(obj)
addToWrapper name, _[name] = obj[name]
# Generate a unique integer id (unique within the entire client session).
# Useful for temporary DOM ids.
idCounter = 0
_.uniqueId = (prefix) ->
(prefix or '') + idCounter++
# By default, Underscore uses **ERB**-style template delimiters, change the
# following template settings to use alternative delimiters.
_.templateSettings = {
start: '<%'
end: '%>'
interpolate: /<%=(.+?)%>/g
# JavaScript templating a-la **ERB**, pilfered from John Resig's
# *Secrets of the JavaScript Ninja*, page 83.
# Single-quote fix from Rick Strahl.
# With alterations for arbitrary delimiters, and to preserve whitespace.
_.template = (str, data) ->
c = _.templateSettings
endMatch = new RegExp("'(?=[^"+c.end.substr(0, 1)+"]*"+escapeRegExp(c.end)+")","g")
fn = new Function 'obj',
'var p=[],print=function(){p.push.apply(p,arguments);};' +
'with(obj||{}){p.push(\'' +
str.replace(/\r/g, '\\r')
.replace(/\n/g, '\\n')
.replace(/\t/g, '\\t')
.replace(c.interpolate, "',$1,'")
.split(c.end).join("p.push('") +
"');}return p.join('');"
if data then fn(data) else fn
# Aliases
# -------
_.forEach = _.each
_.foldl = _.inject = _.reduce
_.foldr = _.reduceRight = _.filter
_.all = _.every
_.any = _.some
_.contains = _.include
_.head = _.first
_.tail =
_.methods = _.functions
# Setup the OOP Wrapper
# ---------------------
# If Underscore is called as a function, it returns a wrapped object that
# can be used OO-style. This wrapper holds altered versions of all the
# underscore functions. Wrapped objects may be chained.
wrapper = (obj) ->
this._wrapped = obj
# Helper function to continue chaining intermediate results.
result = (obj, chain) ->
if chain then _(obj).chain() else obj
# A method to easily add functions to the OOP wrapper.
addToWrapper = (name, func) ->
wrapper.prototype[name] = ->
args = _.toArray arguments args, this._wrapped
result func.apply(_, args), this._chain
# Add all ofthe Underscore functions to the wrapper object.
_.mixin _
# Add all mutator Array functions to the wrapper.
_.each ['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], (name) ->
method = Array.prototype[name]
wrapper.prototype[name] = ->
method.apply(this._wrapped, arguments)
result(this._wrapped, this._chain)
# Add all accessor Array functions to the wrapper.
_.each ['concat', 'join', 'slice'], (name) ->
method = Array.prototype[name]
wrapper.prototype[name] = ->
result(method.apply(this._wrapped, arguments), this._chain)
# Start chaining a wrapped Underscore object.
wrapper::chain = ->
this._chain = true
# Extracts the result from a wrapped and chained object.
wrapper::value = -> this._wrapped
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