conductor

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A modern & functional JavaScript utility library

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# transformers ## general description Transformers are utility function which _decorate_ reducers: they take a reducer as input, and output another reducer, with added functionality. They are extremely useful when used with transduce, as they are very modular and thus easily composable. ## some definitions ### reducer A **reducer** is a function whose role is to merge an _item_ into an _accumulator_ \(a entity containing already merged values\). Usually, a reducer is called several times while iterating over an iterable. For example, Array.prototype.push is a reducer: it takes an accumulator \(the array\) and an item, and merges the item into the array. In conductor, reducers have the following type signature: ```erlang reducer :: (Any accumulator, Any value, Any index, Collection collection) => Any value ``` ### transformer A transformer is a function whose role is to decorate \(add functionality\) to a reducer. It accepts an input reducer, and outputs another reducer. Transformers have the following type signature: ```erlang transformer :: Reducer input => Reducer output ``` ### transducer ```erlang transducer :: (Transformer transformer, Reducer reducer, Any seed, Collection collection) => Any value ```