Add support for nested struct pointers #87 (#92)

* Add support for nested struct pointers #87

* Add comment about struct pointers

* Add inner struct pointer nil test

* Add isValidStructPointer function

* Add omitempty test

Author: frozzare

encoder.go

@@ -40,6 +40,11 @@ func (e *Encoder) SetAliasTag(tag string) {
 	e.cache.tag = tag
 }
 
+// isValidStructPointer test if input value is a valid struct pointer.
+func isValidStructPointer(v reflect.Value) bool {
+	return v.Type().Kind() == reflect.Ptr && v.Elem().IsValid() && v.Elem().Type().Kind() == reflect.Struct
+}
+
 func isZero(v reflect.Value) bool {
 	switch v.Kind() {
 	case reflect.Func:
@@ -80,6 +85,12 @@ func (e *Encoder) encode(v reflect.Value, dst map[string][]string) error {
 			continue
 		}
 
+		// Encode struct pointer types if the field is a valid pointer and a struct.
+		if isValidStructPointer(v.Field(i)) {
+			e.encode(v.Field(i).Elem(), dst)
+			continue
+		}
+
 		encFunc := typeEncoder(v.Field(i).Type(), e.regenc)
 
 		// Encode non-slice types and custom implementations immediately.

encoder_test.go

@@ -375,6 +375,25 @@ func TestEncoderWithOmitempty(t *testing.T) {
 	valsExist(t, "f09", []string{"test"}, vals)
 }
 
+type E6 struct {
+	F01 *inner
+	F02 *inner
+	F03 *inner `schema:",omitempty"`
+}
+
+func TestStructPointer(t *testing.T) {
+	vals := map[string][]string{}
+	s := E6{
+		F01: &inner{2},
+	}
+
+	encoder := NewEncoder()
+	encoder.Encode(&s, vals)
+	valExists(t, "F12", "2", vals)
+	valExists(t, "F02", "null", vals)
+	valNotExists(t, "F03", vals)
+}
+
 func TestRegisterEncoderCustomArrayType(t *testing.T) {
 	type CustomInt []int
 	type S1 struct {