add has method

docs/api/state.md

@@ -130,6 +130,22 @@ if ratio, ok := app.State().GetFloat64("scalingFactor"); ok {
 }
 ```
 
+### Has
+
+Has checks if a key exists in the State.
+
+```go title="Signature"
+func (s *State) Has(key string) bool
+```
+
+**Usage Example:**
+
+```go
+if app.State().Has("appName") {
+    fmt.Println("App Name is set.")
+}
+```
+
 ### Delete
 
 Delete removes a key-value pair from the State.

state.go

@@ -84,6 +84,13 @@ func (s *State) GetFloat64(key string) (float64, bool) {
 	return 0, false
 }
 
+// Has checks if a key is present in the State.
+// It returns a boolean indicating if the key is present.
+func (s *State) Has(key string) bool {
+	_, ok := s.Get(key)
+	return ok
+}
+
 // Delete removes a key-value pair from the State.
 func (s *State) Delete(key string) {
 	s.dependencies.Delete(key)

state_test.go

@@ -120,6 +120,15 @@ func TestState_MustGet(t *testing.T) {
 	})
 }
 
+func TestState_Has(t *testing.T) {
+	t.Parallel()
+
+	st := newState()
+
+	st.Set("key", "value")
+	require.True(t, st.Has("key"))
+}
+
 func TestState_Delete(t *testing.T) {
 	t.Parallel()
 	st := newState()
@@ -424,6 +433,22 @@ func BenchmarkState_GetStateWithDefault(b *testing.B) {
 	}
 }
 
+func BenchmarkState_Has(b *testing.B) {
+	b.ReportAllocs()
+
+	st := newState()
+	n := 1000
+	// pre-populate the state
+	for i := 0; i < n; i++ {
+		st.Set("key"+strconv.Itoa(i), i)
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		st.Has("key" + strconv.Itoa(i%n))
+	}
+}
+
 func BenchmarkState_Delete(b *testing.B) {
 	b.ReportAllocs()