[TASK] TRK-1974 Add map reindex function (#30)

gofp/reindex.go

@@ -0,0 +1,12 @@
+package gofp
+
+// Reindex apply a function to all elements on an map
+func Reindex[InK, OutK comparable, InV, OutV any](m map[InK]InV, fn func(InK, InV) (OutK, OutV)) (res map[OutK]OutV) {
+	res = make(map[OutK]OutV, len(m))
+	for k, v := range m {
+		rK, rV := fn(k, v)
+		res[rK] = rV
+	}
+
+	return
+}

gofp/reindex_test.go

@@ -0,0 +1,91 @@
+package gofp_test
+
+import (
+	"strconv"
+	"testing"
+
+	. "github.com/msales/gox/gofp"
+)
+
+func TestReindex_Int64ToIn32(t *testing.T) {
+	got := Reindex(map[int64]int64{1: 1, 2: 2, 3: 3}, func(key, val int64) (int32, int32) {
+		return int32(key), int32(val)
+	})
+
+	want := map[int32]int32{1: 1, 2: 2, 3: 3}
+
+	if len(want) != len(got) {
+		t.Errorf("Got %+v, want %+v", got, want)
+		return
+	}
+
+	for k, v := range want {
+		if v != got[k] {
+			t.Errorf("Got %+v, want %+v", got, want)
+		}
+	}
+}
+
+func TestReindex_StringToStruct(t *testing.T) {
+	got := Reindex(map[string]string{
+		"1": "1",
+		"2": "2",
+		"3": "3",
+	}, func(key, val string) (string, testID) {
+		id, _ := strconv.ParseInt(val, 10, 64)
+		return key, testID{ID: id}
+	})
+
+	want := map[string]testID{
+		"1": {ID: 1},
+		"2": {ID: 2},
+		"3": {ID: 3},
+	}
+
+	if len(want) != len(got) {
+		t.Errorf("Got %+v, want %+v", got, want)
+		return
+	}
+
+	for k, v := range want {
+		if v != got[k] {
+			t.Errorf("Got %+v, want %+v", got, want)
+		}
+	}
+}
+
+func BenchmarkReindex_Int64ToIn32(b *testing.B) {
+	original := map[int64]int64{
+		1: 1,
+		2: 2,
+		3: 3,
+		4: 4,
+		5: 5,
+		6: 6,
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		Reindex(original, func(key, val int64) (int32, int32) {
+			return int32(key), int32(val)
+		})
+	}
+}
+
+func BenchmarkReindex_StringToStruct(b *testing.B) {
+	original := map[string]string{
+		"1": "1",
+		"2": "2",
+		"3": "2",
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		Reindex(original, func(key, val string) (string, testID) {
+			id, _ := strconv.ParseInt(val, 10, 64)
+			return key, testID{ID: id}
+		})
+	}
+}