Method MapErr

iter/map.go:48–65

MapErr applies f to each element of the input, returning the mapped result and a combined error of all returned errors. Map uses up to the configured Mapper's maximum number of goroutines.

(input []T, f func(*T) (R, error))

//
// Map uses up to the configured Mapper's maximum number of goroutines.
func (m Mapper[T, R]) MapErr(input []T, f func(*T) (R, error)) ([]R, error) {
	var (
		res    = make([]R, len(input))
		errMux sync.Mutex
		errs   error
	)
	Iterator[T](m).ForEachIdx(input, func(i int, t *T) {
		var err error
		res[i], err = f(t)
		if err != nil {
			errMux.Lock()
			// TODO: use stdlib errors once multierrors land in go 1.20
			errs = multierror.Join(errs, err)
			errMux.Unlock()
		}
	})
	return res, errs
}