marcinnajder/powerseq

installation and usage

npm install powerseq

executing single operator

import { filter } from "powerseq";

for(var item of filter([1,2,3,4,5], x => x % 2 === 0)){
    console.log(item);
}

chaining many operators

import { Enumerable } from "powerseq/enumerable";  
// use 'Enumerable' class ONLY on the server side !! (use 'pipe' method on the client side )

const items = Enumerable
    .range(1,Number.MAX_VALUE)
    .filter( x => x % 2 === 0)
    .take(5)
    .reverse()
    .toarray();

console.log(items);

chaining many operators using pipe method (it allows code tree shaking)

import { pipe, range, filter, take, reverse, toarray } from "powerseq";

const items = pipe(
    range(1, Number.MAX_VALUE),
    filter(x => x % 2 === 0),
    take(5),
    reverse(),
    toarray());

console.log(items);

most of the operators can be used as a single operator (filter([1,2,3,4,5], x => x % 2 === 0)) or as a part of the operator chain pipe([1, 2, 3, 4, 5], filter(x => x % 2 === 0), ... ).But some operators have special counterparts (concatp, defaultifemptyp, includesp, sequenceequalp, zipp) when used with pipe, so we call concat([1,2,3], [4,5,6]) but we have to call pipe([1,2,3], concatp([4,5,6]), ... ) if we want to chain concat with other operators.

operators

• each operator below has tooltip with documentation
• click to see mapping powerseq operators to LINQ, RxJS, JS Array, lodash, F#

enumerable