Golang Samber Lo

1. Prefer stdlib when available — slices.Contains, slices.Sort, maps.Keys carry no dependency. Use lo for transforms the stdlib doesn't offer (Map, Filter, Reduce, GroupBy, Chunk, Flatten) 2. Compose lo functions — chain lo.Filter → lo.Map → lo.GroupBy instead of writing nested loops. Each function is a building block 3. Profile before optimizing — switch from lo to lom/lop only after go tool pprof confirms allocation or CPU as the bottleneck 4. Use error variants — prefer lo.MapErr over lo.Map + manual error collection. Error variants stop early and propagate cleanly 5. Use lo.Must only in tests and init — in production, handle errors explicitly