+ Underscore is a + utility-belt library for Javascript that provides a lot of the + functional programming support that you would expect in + Prototype.js + (or Ruby), + but without extending any of the built-in Javascript objects. It's the + tie to go along with jQuery's tux. +
+ ++ Underscore provides 43-odd functions that support both the usual + functional suspects: map, select, invoke — + as well as more specialized helpers: function binding, javascript + templating, deep equality testing, and so on. It delegates to the built-in + functions, if present, so + Javascript 1.6 + compliant browsers will use the + native implementations of forEach, map, filter, + every and some. +
+ ++ Underscore includes a complete Test & Benchmark Suite + for your perusal. +
+ +
+ Collections
+
+ each, map,
+ inject, detect, select, reject, all,
+ any, include, invoke, pluck, max,
+ min, sortBy, sortedIndex, toArray,
+ size
+
+ Arrays
+
+ first, last,
+ compact, flatten, without, uniq,
+ intersect, zip, indexOf
+
+ Objects
+
+ keys, values,
+ extend, clone, isEqual, isElement,
+ isArray, isFunction, isUndefined, toString
+
+
+ Functions
+
+ bind, bindAll, delay,
+ defer, wrap
+
+ Utility
+
+ uniqueId, template
+
+ each_.each(list, iterator, [context])
+
+ Iterates over a list of elements, yielding each in turn to an iterator
+ function. The iterator is bound to the context object, if one is
+ passed. If list is a Javascript object, a pair with key
+ and value properties will be yielded. Delegates to the native
+ forEach method if it exists.
+
+_.each([1, 2, 3], function(num){ alert(num); });
+=> alerts each number in turn...
+
+
+ map_.map(list, iterator, [context])
+
+ Produces a new array of values by mapping each value in list
+ through a transformation function (iterator). If the native
+ map method exists, it will be used instead.
+
+_.map([1, 2, 3], function(num){ return num * 3 });
+=> [3, 6, 9]
+
+
+ inject_.inject(list, memo, iterator, [context])
+
+ Also known as reduce and foldl, inject reduces a
+ list of values into a single value. Memo is the initial state
+ of the reduction, and each successive step of it should be returned by
+ iterator.
+
+var sum = _.inject([1, 2, 3], 0, function(memo, num){ return memo + num });
+=> 6
+
+
+
+ detect_.detect(list, iterator, [context])
+
+ Looks through each value in the list, returning the first one that
+ passes a truth test (iterator). The function returns as
+ soon as it finds the true element, and doesn't continue to traverse
+ the list.
+
+var even = _.detect([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
+=> 2
+
+
+
+ select_.select(list, iterator, [context])
+
+ Looks through each value in the list, returning an array of all
+ the values that pass a truth test (iterator). Delegates to the
+ native filter method, if it exists.
+
+var evens = _.select([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
+=> [2, 4, 6]
+
+
+
+ reject_.reject(list, iterator, [context])
+
+ Returns the values in list without the elements that the truth
+ test (iterator) passes. The opposite of select.
+
+var odds = _.reject([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
+=> [1, 3, 5]
+
+
+
+ all_.(list, [iterator], [context])
+
+ Returns true if all of the values in the list pass the iterator
+ truth test. If an iterator is not provided, the truthy value of
+ the element will be used instead. Delegates to the native method every, if
+ present.
+
+_.all([true, 1, null, 'yes']); +=> false ++ +
+ any_.(list, iterator, [context])
+
+ Returns true if any of the values in the list pass the
+ iterator truth test. Short-circuits and stops traversing the list
+ if a true element is found. Delegates to the native method some,
+ if present.
+
+_.any([null, 0, 'yes', false]); +=> true ++ +
+ include_.(list, iterator, [context])
+
+
+
++ +
+ invoke_.(list, iterator, [context])
+
+
+
++ +
+ pluck_.(list, iterator, [context])
+
+
+
++ +
+ max_.(list, iterator, [context])
+
+
+
++ +
+ min_.(list, iterator, [context])
+
+
+
++ +
+ sortBy_.(list, iterator, [context])
+
+
+
++ +
+ sortedIndex_.(list, iterator, [context])
+
+
+
++ +
+ toArray_.(list, iterator, [context])
+
+
+
++ +
+ size_.(list, iterator, [context])
+
+
+
++ +