Core Maptosliceerr - Lo

Transforms a map into a slice by applying an predicate to each key/value pair. Returns an error if the iteratee function fails, stopping iteration immediately.

m := map[int]int64{1: 4, 2: 5, 3: 6}
s, err := lo.MapToSliceErr(m, func(k int, v int64) (string, error) {
    if k == 2 {
        return "", fmt.Errorf("key 2 not allowed")
    }
    return fmt.Sprintf("%d_%d", k, v), nil
})
// []string(nil), error("key 2 not allowed")

m := map[int]int64{1:4, 2:5, 3:6}
s, err := lo.MapToSliceErr(m, func(k int, v int64) (string, error) {
    return fmt.Sprintf("%d_%d", k, v), nil
})
// []string{"1_4", "2_5", "3_6"}, nil