transduce-async

Transduce Async

Use Transducers with async iterators and observables by supporting Promises in iterators and transformers. Inspired by this talk from Erik Meijer.

Works with transduce, transducers-js or transducers.js.

Also works with any-promise library (a pollyfill, es6-promise, promise, native-promise-only, bluebird, rsvp, when, q).

Just install your transducers and Promise library preference and it will be auto detected and used.

API:

defer: function();
delay: function(wait);
compose: function(/*args*/);
transduce: function(xf, f, init, coll);
reduce: function(f, init, coll);
toArray: function(xf?, coll);

defer

Create a deferred transducer that allows wrapped transformer to step or result a Promise in addition to a value. All items will be queued and processed in order. The wrapped transformer is called with value of resolved Promise.

delay

Create a deferred transducer that delays step of wrapped transformer by wait milliseconds. All items will be queued and delayed and step will return a promise that will resolve after wait milliseconds for each item.

compose

Like a normal compose, except all arguments are interleaved with defer. This allows any transducer in composed pipeline to step or result a Promise in addition to a value. The wrapped transformer is called with value of resolved Promise.

transduce

Like a normal transduce, except init and coll can be a Promise and xf can be a deferred transducer. The value of coll can be anything that can be converted to an iterator. The return value is a Promise for the result of the transformation.

reduce

Like a normal reduce, except init and coll can be a Promise and xf can be a deferred transducer. The value of coll can be anything that can be converted to an iterator. The return value is a Promise for the result of the reduction.

toArray

Convenience function to transduce into an array with an optional transformation. The return value is a Promise for an array.