indexBy_.indexBy(list, iteratee, [context]) Given a list, and an iteratee function that returns a key for each element

isNumber_.isNumber(object) Returns true if object is a Number (including NaN).

groupBy_.groupBy(list, iteratee, [context]) Splits a collection into sets, grouped by the result of running each value through iteratee

reduce_.reduce(list, iteratee, [memo], [context]) Aliases: inject, foldl Also known as inject

isNull_.isNull(object) Returns true if the value of object is null.

unescape_.unescape(string) The opposite of escape

has_.has(object, key) Does the object contain the given key? Identical to object.hasOwnProperty(key), but uses a safe reference

isUndefined_.isUndefined(value) Returns true if value is undefined.

isNaN_.isNaN(object) Returns true if object is NaN. Note: this is not the same as the native isNaN

map_.map(list, iteratee, [context]) Alias: collect Produces a new array of values by mapping each