functional-streams
v2.0.2
Published
Native implementations of map, reduce, and batch, to act on streams.
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Functional Streams
Provides four native Node streams that mirror the behaviour of basic FP array manipulations. As they extend
directly from Node native streams, they can be pipe
d and emit events as you are used to. No runtime dependencies, typescript definitions included.
const FS = require('functional-streams');
Map
const mapStream = new FS.Map((n) => n + 2);
Filter
const filterStream = new FS.Filter((n) => n % 2 === 0);
Reduce
Provides a then
method so this can be used in a promise-like fashion to get the end result.
const reduceStream = new FS.Reduce((sum, n) => sum + n, 0);
reduceStream.write(0);
reduceStream.write(1);
reduceStream.write(2);
reduceStream.write(3);
reduceStream.end(4);
reduceStream.then((result) => {
console.log(result); // 10
});
Batch
const batchStream = new FS.Batch(3);
batchStream.write(0);
batchStream.write(1);
batchStream.write(2);
batchStream.write(3);
batchStream.end(4);
batchStream.read(); // [0, 1, 2];
batchStream.read(); // [3, 4];