filter() function

Return Iterable/AsyncIterable of all elements f returns truthy for

Signature:

declare function filter<A>(f: BooleanConstructor, iterable: Iterable<A>): IterableIterator<TruthyTypesOf<A>>;

Example

const iter = filter((a)=> a % 2 === 0, [0, 1, 2, 3, 4, 5, 6]);
iter.next() // {done:false, value: 0}
iter.next() // {done:false, value: 2}
iter.next() // {done:false, value: 4}
iter.next() // {done:false, value: 6}
iter.next() // {done:true, value: undefined}

// with pipe
pipe(
 [0, 1, 2, 3, 4, 5, 6],
 filter(a => a % 2 === 0),
 toArray,
); // [0, 2, 4, 6]

await pipe(
 Promise.resolve([0, 1, 2, 3, 4, 5, 6]),
 filter(a => a % 2 === 0),
 toArray,
); // [0, 2, 4, 6]

// if you want to use asynchronous callback
await pipe(
 Promise.resolve([0, 1, 2, 3, 4, 5, 6]),
 toAsync,
 filter(async a => a % 2 === 0),
 toArray,
); // [0, 2, 4, 6]

// toAsync
await pipe(
 [Promise.resolve(0), Promise.resolve(1), Promise.resolve(2), Promise.resolve(3),
  Promise.resolve(4), Promise.resolve(5), Promise.resolve(6)],
 toAsync,
 filter(a => a % 2 === 0),
 toArray,
); // [0, 2, 4, 6]

Try It

see pipe, toAsync, toArray

Open Source Code