amp/docs/iterators/transformation.md

layout	title	permalink
docs	Iterator Transformation	/iterators/transformation

Amp provides some common transformation helpers for iterators: map, filter and toArray.

Further primitives are very easy to implement using Producer with these as examples.

map()

map() accepts an Iterator and a callable $onEmit that can transform each value into another value.

filter()

filter() accepts an Iterator and a callable $filter. If $filter($value) returns false the value gets filtered, otherwise the value is retained in the resulting Iterator.

toArray()

toArray() accepts an Iterator and returns a Promise which resolves to an array of all the items from the iterator.