@lordofdestiny/streams-ts

streams-ts

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TypeScript implementation of the Streams API for Node.js. Inspired by the Java 8 Stream API and Rust's Iterator trait.

Library is still in development and not yet ready for production use. It's mostly feature complete, but there are still some missing methods and some methods, like cycle and reverse.

Library is written in TypeScript and compiled to ES6. You can use it in both Node.js and the browser, with both TypeScript and JavaScript.

All methods are lazy and return a new Stream object. Even so, focus of the library was more on the API design and less on performance.

Library is heavily tested with Jest.

Examples

import {Stream} from '@lordofdestiny/streams-ts';

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

const result = Stream.from(arr)
    .filter(x => x % 2 === 0)
    .map(x => x * 2)
    .toArray();

console.log(result); // [4, 8, 12, 16, 20]

const result2 = Stream.from(arr)
    .filter(x => x % 2 === 0)
    .map(x => x * 2)
    .reduce((acc, x) => acc + x);

console.log(result2); // 60

const result3 = Stream.from(arr)
    .filter(x => x % 2 === 0)
    .map(x => x * 2)
    .findFirst((_) => true);

console.log(result3); // 4

/* We need to make an explicit cast because
   TypeScript can't infer the type of the chunked stream
 */
const stream4 = Stream.from(arr).chunk(2) as Stream<[number, number]>;
const result4 = stream4.toMap();

console.log(result4); // Map { 1 => 2, 3 => 4, 5 => 6, 7 => 8, 9 => 10 }