/
each.ts
70 lines (60 loc) · 1.73 KB
/
each.ts
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import { isAsyncIterable, isIterable, isPromise } from "./_internal/utils";
import type IterableInfer from "./types/IterableInfer";
import type ReturnValueType from "./types/ReturnValueType";
function sync<A, B = unknown>(f: (a: A) => B, iterable: Iterable<A>): void {
for (const a of iterable) {
f(a);
}
}
async function async<A, B = unknown>(
f: (a: A) => B,
iterable: AsyncIterable<A>,
): Promise<void> {
for await (const item of iterable) {
const value = f(item);
if (isPromise(value)) {
await value;
}
}
}
/**
* Iterates over Iterable/AsyncIterable, applying each in turn to `f`.
*
* @example
* ```ts
* each(console.log, [1, 2, 3]); // log 1, 2, 3
* ```
*
* {@link https://codesandbox.io/s/fxts-each-kvz6w | Try It}
*/
// prettier-ignore
function each<A, B = unknown>(
f: (a: A) => B,
iterable: Iterable<A>
): void;
function each<A, B = unknown>(
f: (a: A) => B,
iterable: AsyncIterable<A>,
): Promise<void>;
function each<
A extends Iterable<unknown> | AsyncIterable<unknown>,
B = unknown,
>(f: (a: IterableInfer<A>) => B): (iterable: A) => ReturnValueType<A, void>;
function each<A extends Iterable<unknown> | AsyncIterable<unknown>, B>(
f: (a: IterableInfer<A>) => B,
iterable?: A,
): void | Promise<void> | ((iterable: A) => ReturnValueType<A, void>) {
if (iterable === undefined) {
return (iterable: A): ReturnValueType<A, void> => {
return each(f, iterable as any) as ReturnValueType<A, void>;
};
}
if (isIterable<IterableInfer<A>>(iterable)) {
return sync(f, iterable);
}
if (isAsyncIterable<IterableInfer<A>>(iterable)) {
return async(f, iterable);
}
throw new TypeError("'iterable' must be type of Iterable or AsyncIterable");
}
export default each;