feat: add Minus func

maputil/map.go

@@ -60,7 +60,7 @@ func Filter[K comparable, V any](m map[K]V, predicate func(key K, value V) bool)
 	return res
 }
 
-// Intersect iterates over maps, return a new map of key and value pairs in all give maps
+// Intersect iterates over maps, return a new map of key and value pairs in all given maps
 func Intersect[K comparable, V any](maps ...map[K]V) map[K]V {
 	if len(maps) == 0 {
 		return map[K]V{}
@@ -92,3 +92,16 @@ func Intersect[K comparable, V any](maps ...map[K]V) map[K]V {
 
 	return res
 }
+
+
+// Minus creates an map of whose key in mapA but not in mapB
+func Minus[K comparable, V any](mapA, mapB map[K]V) map[K]V {
+	res := make(map[K]V)
+
+	for k, v := range mapA {
+		if _, ok := mapB[k]; !ok {
+			res[k] = v
+		}
+	}
+	return res
+}

maputil/map_test.go

@@ -130,3 +130,21 @@ func TestIntersect(t *testing.T) {
 	assert.Equal(map[string]int{"a": 1, "b": 2}, Intersect(m1, m2))
 	assert.Equal(map[string]int{"a": 1}, Intersect(m1, m2, m3))
 }
+
+func TestMinus(t *testing.T) {
+	assert := internal.NewAssert(t, "TestMinus")
+
+	m1 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+	}
+
+	m2 := map[string]int{
+		"a": 11,
+		"b": 22,
+		"d": 33,
+	}
+
+	assert.Equal(map[string]int{"c": 3}, Minus(m1, m2))
+}