Flatmap
Flatmap flattens the input slice element into the new slice. FlatMap maps every element with the help of a mapper function, then flattens the input slice element into the new slice.
package main
import (
"fmt"
u "github.com/rjNemo/underscore"
)
func main() {
nums := []int{1, 2, 3, 4}
mapper := func(n int) []int { return []int{(n - 1) * n, (n) * n} }
res := u.Flatmap(nums, mapper)
fmt.Println(res) // {0, 1, 2, 4, 6, 9, 12, 16}
}