[p-filter] Add definitions (#2898)

definitions/npm/p-filter_v1.x.x/flow_v0.70.x-/p-filter_v1.x.x.js

@@ -0,0 +1,7 @@
+declare module 'p-filter' {
+  declare export default function PFilter<T>(
+    input: Iterable<Promise<T> | T>,
+    filterer: (element: T, index: number) => boolean | Promise<boolean>,
+    options?: { concurrency?: number },
+  ): Promise<Array<T>>;
+}

definitions/npm/p-filter_v1.x.x/test_p-filter_v1.x.x.js

@@ -0,0 +1,35 @@
+import pFilter from 'p-filter';
+import { it } from 'flow-typed-test';
+
+it('handles correct inputs and return type', () => {
+  (pFilter([1, 2, 3], (el: number, index: number) => true): Promise<
+    Array<number>,
+  >);
+  (pFilter(
+    ['a', 'b', Promise.resolve('c')],
+    (el: string, index: number) => false,
+    { concurrency: 2 },
+  ): Promise<Array<string>>);
+});
+
+it('errors on invalid filterer element type', () => {
+  // $ExpectError
+  pFilter(['a', 'b', Promise.resolve(3)], (el: string, index: number) => true);
+});
+
+it('errors on invalid filterer return type', () => {
+  // $ExpectError
+  pFilter([1, 2, Promise.resolve(3)], (el: number, index: number) => null);
+});
+
+it('errors on invalid return type', () => {
+  // $ExpectError
+  (pFilter([1, 2, 3], (el: number, index: number) => true): Promise<
+    Array<string>,
+  >);
+});
+
+it('errors on invalid options', () => {
+  // $ExpectError
+  pFilter([1, 2, 3], (el: number, index: number) => true, { concurrency: '1' });
+});