maputil: IsDisjoint (#43)

Verifies map a and map b have no keys in common.

if it returns true then the maps are disjoint otherwise a join in some form available

maputil/map.go

@@ -108,3 +108,13 @@ func Minus[K comparable, V any](mapA, mapB map[K]V) map[K]V {
 	}
 	return result
 }
+
+// IsDisjoint two map are disjoint if they have no keys in common
+func IsDisjoint[K comparable, V any](mapA, mapB map[K]V) bool {
+	for k := range mapA {
+		if _, ok := mapB[k]; ok {
+			return false
+		}
+	}
+	return true
+}

maputil/map_test.go

@@ -148,3 +148,25 @@ func TestMinus(t *testing.T) {
 
 	assert.Equal(map[string]int{"c": 3}, Minus(m1, m2))
 }
+
+func TestIsDisjoint(t *testing.T) {
+	assert := internal.NewAssert(t, "TestMinus")
+
+	m1 := map[string]int{
+		"a": 1,
+		"b": 2,
+		"c": 3,
+	}
+
+	m2 := map[string]int{
+		"d": 22,
+	}
+
+	assert.Equal(true, IsDisjoint(m1, m2))
+
+	m3 := map[string]int{
+		"a": 22,
+	}
+
+	assert.Equal(false, IsDisjoint(m1, m3))
+}