compose_.compose(*functions) Returns the composition of a list of functions, where each function consumes the return value of the function that follows. In math terms, composing the functions f(), g(), and h() produces f(g(h())). var greet = function(name){ return "hi: " + name; }; var exclaim = function(statement){ return statement.toUpperCase() + "!"; }; var welcome = _.compose(greet, exclaim); welcome('moe'); => 'hi: MOE!'

compact_.compact(array) Returns a copy of the array with all falsy values removed. In JavaScript, false, null, 0, "", undefined and NaN are all falsy. _.compact([0, 1, false, 2, '', 3]); => [1, 2, 3]

map_.map(list, iteratee, [context]) Alias: collect Produces a new array of values by mapping each value in list through a transformation function (iteratee). The iteratee is passed three arguments: the value, then the index (or key) of the iteration, and finally a reference to the entire list. _.map([1, 2, 3], function(num){ return num * 3; }); => [3, 6, 9] _.map({one: 1, two: 2, three: 3}, function(num, key){ return num * 3; }); => [3, 6, 9] _.map([[1, 2], [3, 4]], _.first); => [1

clone_.clone(object) Create a shallow-copied clone of the provided plain object. Any nested objects or arrays will be copied by reference, not duplicated. _.clone({name: 'moe'}); => {name: 'moe'};

chain_.chain(obj) Returns a wrapped object. Calling methods on this object will continue to return wrapped objects until value is called. var stooges = [{name: 'curly', age: 25}, {name: 'moe', age: 21}, {name: 'larry', age: 23}]; var youngest = _.chain(stooges) .sortBy(function(stooge){ return stooge.age; }) .map(function(stooge){ return stooge.name + ' is ' + stooge.age; }) .first() .value(); => "moe is 21"

bindAll_.bindAll(object, *methodNames) Binds a number of methods on the object, specified by methodNames, to be run in the context of that object whenever they are invoked. Very handy for binding functions that are going to be used as event handlers, which would otherwise be invoked with a fairly useless this. methodNames are required. var buttonView = { label : 'underscore', onClick: function(){ alert('clicked: ' + this.label); }, onHover: function(){ console.log('hovering: ' + this

bind_.bind(function, object, *arguments) Bind a function to an object, meaning that whenever the function is called, the value of this will be the object. Optionally, pass arguments to the function to pre-fill them, also known as partial application. For partial application without context binding, use partial. var func = function(greeting){ return greeting + ': ' + this.name }; func = _.bind(func, {name: 'moe'}, 'hi'); func(); => 'hi: moe'

before_.before(count, function) Creates a version of the function that can be called no more than count times. The result of the last function call is memoized and returned when count has been reached. var monthlyMeeting = _.before(3, askForRaise); monthlyMeeting(); monthlyMeeting(); monthlyMeeting(); // the result of any subsequent calls is the same as the second call

extendOwn_.extendOwn(destination, *sources) Alias: assign Like extend, but only copies own properties over to the destination object.

some_.some(list, [predicate], [context]) Alias: any Returns true if any of the values in the list pass the predicate truth test. Short-circuits and stops traversing the list if a true element is found. _.some([null, 0, 'yes', false]); => true