maptools/SortedKeysNoCase() (#17)

maptools/sort.go

@@ -1,6 +1,9 @@
 package maptools
 
-import "sort"
+import (
+	"sort"
+	"strings"
+)
 
 func SortedKeys[V any](m map[string]V) []string {
 	keys := make([]string, 0, len(m))
@@ -12,3 +15,22 @@ func SortedKeys[V any](m map[string]V) []string {
 
 	return keys
 }
+
+func SortedKeysNoCase[V any](m map[string]V) []string {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+
+	sort.Slice(keys, func(i, j int) bool {
+		li, lj := strings.ToLower(keys[i]), strings.ToLower(keys[j])
+		if li == lj {
+			// differ only by case, sort by original key
+			// will have uppercase first
+			return keys[i] < keys[j]
+		}
+		return li < lj
+	})
+
+	return keys
+}

maptools/sort_test.go

@@ -40,3 +40,43 @@ func TestSortedKeys(t *testing.T) {
 		})
 	}
 }
+
+func TestSortedKeysNoCase(t *testing.T) {
+	tests := []struct {
+		name string
+		m    map[string]int
+		want []string
+	}{
+		{
+			name: "empty map",
+			m:    map[string]int{},
+			want: []string{},
+		},
+		{
+			name: "single element",
+			m:    map[string]int{"a": 1},
+			want: []string{"a"},
+		},
+		{
+			name: "multiple elements with different cases",
+			m:    map[string]int{"b": 2, "A": 1, "C": 3},
+			want: []string{"A", "b", "C"},
+		},
+		{
+			name: "elements with same values and different cases",
+			m:    map[string]int{"b": 2, "A": 2, "c": 2},
+			want: []string{"A", "b", "c"},
+		},
+		{
+			name: "mixed case elements",
+			m:    map[string]int{"Banana": 1, "apple": 2, "Cherry": 3, "banana": 4, "Apple": 5, "cherry": 6},
+			want: []string{"Apple", "apple", "Banana", "banana", "Cherry", "cherry"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, SortedKeysNoCase(tt.m))
+		})
+	}
+}