package stringutil

import "sort"

func MapKeys(m map[string]string) <-chan string {
	ch := make(chan string)
	if m == nil {
		close(ch)
	} else {
		go func(ch chan<- string) {
			defer close(ch)
			keys := make([]string, 0, len(m))
			for k := range m {
				keys = append(keys, k)
			}
			sort.Strings(keys)
			for _, k := range keys {
				ch <- k
			}
		}(ch)
	}
	return ch
}