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Generic Methods
You can also make generic methods on non-generic structs in Go 1.27. Say we have this repeater struct:
type repeater struct {
count int
}
It has a Repeat method that creates a new slice with count instances of the given value:
func (r repeater) Repeat[T any](value T) []T {
result := make([]T, r.count)
for i := range result {
result[i] = value
}
return result
}
Now we can reuse it to create slices of different types:
r := repeater{count: 3}
fmt.Println(r.Repeat("Go"))
// [Go Go Go]
fmt.Println(r.Repeat(42))
// [42 42 42]
The struct isn't generic, only the method is!
Assignment
Textio's inbox mixes event types. Emails and Receipts duplicate the same filtering logic. Replace them with one generic Select method.