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/** * Taken from * https://github.com/denoland/node_deno_shims/blob/578ff710f8441e043b7625411c4b4fde3318afb1/packages/shim-deno/src/deno/internal/iterutil.ts#L1-L5 */export function* map<Initial, Transformed>(  iterable: Iterable<Initial>,  f: (t: Initial) => Transformed,): Generator<Transformed, void, unknown> {  for (const item of iterable) {    yield f(item);  }}
/** * Taken from * https://github.com/denoland/node_deno_shims/blob/578ff710f8441e043b7625411c4b4fde3318afb1/packages/shim-deno/src/deno/internal/iterutil.ts#L7-L14 */export async function* mapAsync<Initial, Transformed>(  iterable: AsyncIterable<Initial>,  f: (t: Initial) => Transformed,): AsyncGenerator<Transformed, void, unknown> {  for await (const item of iterable) {    yield f(item);  }}
/** * Taken from * https://github.com/denoland/node_deno_shims/blob/578ff710f8441e043b7625411c4b4fde3318afb1/packages/shim-deno/src/deno/internal/iterutil.ts#L16-L39 */export async function* merge<Type>(iterables: AsyncIterable<Type>[]) {  const racers = new Map<AsyncIterator<Type>, Promise<IteratorResult<Type>>>(    map(      map(iterables, (iterable) => iterable[Symbol.asyncIterator]()),      (iterable) => [iterable, iterable.next()],    ),  );
  while (racers.size > 0) {    const winner = await Promise.race(      map(        racers.entries(),        ([iterable, promise]) =>          promise.then((result) => ({ result, iterable })),      ),    );
    if (winner.result.done) {      racers.delete(winner.iterable);    } else {      yield await winner.result.value;      racers.set(winner.iterable, winner.iterable.next());    }  }}