go-best-practiceslisted
Install: claude install-skill aiskillstore/marketplace
# Go Best Practices
Follows type-first, functional, and error handling patterns from CLAUDE.md. This skill covers language-specific idioms only.
## Make Illegal States Unrepresentable
Use Go's type system to prevent invalid states at compile time.
**Custom types for domain primitives:**
```go
// Distinct types prevent mixing up IDs
type UserID string
type OrderID string
func GetUser(id UserID) (*User, error) {
// Compiler prevents passing OrderID here
}
// Methods attach behavior to the type
func (id UserID) String() string {
return string(id)
}
```
**Interfaces for behavior contracts:**
```go
// Define what you need, not what you have
type UserRepository interface {
GetByID(ctx context.Context, id UserID) (*User, error)
Save(ctx context.Context, user *User) error
}
// Accept interfaces, return structs
func ProcessInput(r io.Reader) ([]byte, error) {
return io.ReadAll(r)
}
```
**Enums with iota and exhaustive switch:**
```go
type Status int
const (
StatusActive Status = iota + 1
StatusInactive
StatusPending
)
func ProcessStatus(s Status) (string, error) {
switch s {
case StatusActive:
return "processing", nil
case StatusInactive:
return "skipped", nil
case StatusPending:
return "waiting", nil
default:
return "", fmt.Errorf("unhandled status: %v", s)
}
}
```
**Functional options for flexible construction:**
```go
type ServerOption func(*Server)
func WithPort(port int) ServerOpt