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

README.md

@@ -292,6 +292,7 @@ import "github.com/duke-git/lancet/v2/maputil"
 - [Merge](https://github.com/duke-git/lancet/blob/main/docs/maputil.md#Merge)
 - [Minus](https://github.com/duke-git/lancet/blob/main/docs/maputil.md#Minus)
 - [Values](https://github.com/duke-git/lancet/blob/main/docs/maputil.md#Values)
+- [IsDisjoint](https://github.com/duke-git/lancet/blob/main/docs/maputil.md#IsDisjoint)
 
 
 ### 11. Mathutil package implements some functions for math calculation.

docs/maputil.md

@@ -301,4 +301,54 @@ func main() {
 
 	fmt.Println(values) // []string{"a", "a", "b", "c", "d"}
 }
+```
+
+### <span id="Values">Values</span>
+<p>Returns a boolean</p>
+
+<b>Signature:</b>
+
+```go
+IsDisjoint[K comparable, V any](mapA, mapB map[K]V) bool
+```
+<b>Example:</b>
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/duke-git/lancet/v2/maputil"
+)
+
+func main() {
+	m1 := map[int]string{
+		1: "a",
+		2: "a",
+		3: "b",
+		4: "c",
+		5: "d",
+	}
+
+	m2 := map[int]string{
+		1: "a",
+		2: "a",
+		3: "b",
+		4: "c",
+		5: "d",
+	}
+	
+	m3 := map[int]string{
+		6: "a",
+	}
+
+	ok := maputil.IsDisjoint(m2, m1)
+
+	fmt.Println(ok) // false
+
+
+	ok = maputil.IsDisjoint(m2, m3)
+
+	fmt.Println(ok) // true
+}
 ```

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))
+}