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filter.ts
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filter.ts
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import { isAsyncIterable } from '../helpers/util';
import { PipeFn } from '../internalTypes';
// prettier-ignore
export function opFilterAsync<T, S extends T>(filterFn: (v: T) => v is S): (iter: AsyncIterable<T>) => AsyncIterable<S>;
// prettier-ignore
export function opFilterAsync<T, S extends Awaited<T>>(filterFn: (v: Awaited<T>) => v is S): (iter: AsyncIterable<T>) => AsyncIterable<S>;
// prettier-ignore
export function opFilterAsync<T>(filterFn: (v: Awaited<T>) => boolean): (iter: AsyncIterable<T>) => AsyncIterable<Awaited<T>>;
// prettier-ignore
export function opFilterAsync<T>(filterFn: (v: Awaited<T>) => Promise<boolean>): (iter: AsyncIterable<T>) => AsyncIterable<Awaited<T>>;
// prettier-ignore
export function opFilterAsync<T>(filterFn: (v: Awaited<T>) => boolean | Promise<boolean>): (iter: AsyncIterable<T>) => AsyncIterable<Awaited<T>> {
async function* fn(iter: Iterable<T> | AsyncIterable<T>) {
for await (const v of iter) {
const pass = await filterFn(v);
if (pass) yield v;
}
}
return fn;
}
export function opFilterSync<T, S extends T>(filterFn: (v: T) => v is S): (iter: Iterable<T>) => Iterable<S>;
export function opFilterSync<T>(filterFn: (v: T) => boolean): (iter: Iterable<T>) => Iterable<T>;
export function opFilterSync<T>(filterFn: (v: T) => boolean): (iter: Iterable<T>) => Iterable<T> {
function* fn(iter: Iterable<T>) {
for (const v of iter) {
if (filterFn(v)) yield v;
}
}
return fn;
}
export function opFilter<T, S extends T>(fn: (v: T) => v is S): PipeFn<T, S>;
export function opFilter<T>(fn: (v: T) => boolean): PipeFn<T, T>;
export function opFilter<T>(fn: (v: T) => boolean): PipeFn<T, T> {
const asyncFn = opFilterAsync(fn);
const syncFn = opFilterSync(fn);
function _(i: Iterable<T>): Iterable<T>;
function _(i: AsyncIterable<T>): AsyncIterable<T>;
function _(i: Iterable<T> | AsyncIterable<T>): Iterable<T> | AsyncIterable<T> {
return isAsyncIterable(i) ? asyncFn(i) : syncFn(i);
}
return _;
}