From c120117c73dfa8ec2222f59bf0e440e0436f16e8 Mon Sep 17 00:00:00 2001
From: Felix Sun <sunfmin@gmail.com>
Date: Thu, 29 Aug 2019 12:04:45 +0800
Subject: [PATCH] Add GetType

---
 README.md       | 69 +++++++++++++++++++++++--------------------------
 example_test.go | 35 +++++++++++++++++++++++++
 get_type.go     | 52 +++++++++++++++++++++++++++++++++++++
 3 files changed, 120 insertions(+), 36 deletions(-)
 create mode 100644 get_type.go

diff --git a/README.md b/README.md
index 406a85e..b4cf6e8 100644
--- a/README.md
+++ b/README.md
@@ -21,42 +21,6 @@ go get github.com/sunfmin/reflectutils
 
 
 
-
-* [Variables](#variables)
-* [Get](#get)
-* [Must Get](#must-get)
-* [Set](#set)
-
-
-## Variables
-``` go
-var NoSuchFieldError = errors.New("no such field.")
-```
-
-
-## Get
-``` go
-func Get(i interface{}, name string) (value interface{}, err error)
-```
-Get value of a struct by path using reflect.
-
-
-
-## Must Get
-``` go
-func MustGet(i interface{}, name string) (value interface{})
-```
-MustGet get value of a struct by path using reflect, return nil if anything in the path is nil
-
-
-
-## Set
-``` go
-func Set(i interface{}, name string, value interface{}) (err error)
-```
-Set value of a struct by path using reflect.
-
-
 By given these structs
 ```go
 	type Person struct {
@@ -355,6 +319,39 @@ If you set a property that don't exists, it gives you an error.
 	// no such field.
 ```
 
+Get Type of a deep nested object
+```go
+	type Variant struct {
+	    Name string
+	}
+	type Product struct {
+	    Variants []*Variant
+	    ByCode   map[string]*Variant
+	}
+	type Obj struct {
+	    MainProduct *Product
+	}
+	
+	var o *Obj
+	
+	fmt.Println(GetType(o, "MainProduct.Variants[0].Name"))
+	fmt.Println(GetType(o, "MainProduct.Variants[0]"))
+	fmt.Println(GetType(o, "MainProduct.Variants"))
+	fmt.Println(GetType(o, "MainProduct"))
+	fmt.Println(GetType(o, "MainProduct.ByCode.abc"))
+	fmt.Println(GetType(o, "MainProduct.ByCode"))
+	fmt.Println(GetType(o, "x123.ByCode"))
+	fmt.Println(GetType(o, "MainProduct.ByCode.abc.NotExist"))
+	//Output:
+	//string
+	//*reflectutils_test.Variant
+	//[]*reflectutils_test.Variant
+	//*reflectutils_test.Product
+	//*reflectutils_test.Variant
+	//map[string]*reflectutils_test.Variant
+	//<nil>
+	//<nil>
+```
 
 
 
diff --git a/example_test.go b/example_test.go
index 837ddc1..138f82f 100644
--- a/example_test.go
+++ b/example_test.go
@@ -306,6 +306,41 @@ func ExampleSet_7notexists() {
 	// no such field.
 }
 
+
+// Get Type of a deep nested object
+func ExampleSet_8gettype() {
+	type Variant struct {
+		Name string
+	}
+	type Product struct {
+		Variants []*Variant
+		ByCode map[string]*Variant
+	}
+	type Obj struct {
+		MainProduct *Product
+	}
+
+	var o *Obj
+
+	fmt.Println(GetType(o, "MainProduct.Variants[0].Name"))
+	fmt.Println(GetType(o, "MainProduct.Variants[0]"))
+	fmt.Println(GetType(o, "MainProduct.Variants"))
+	fmt.Println(GetType(o, "MainProduct"))
+	fmt.Println(GetType(o, "MainProduct.ByCode.abc"))
+	fmt.Println(GetType(o, "MainProduct.ByCode"))
+	fmt.Println(GetType(o, "x123.ByCode"))
+	fmt.Println(GetType(o, "MainProduct.ByCode.abc.NotExist"))
+	//Output:
+	//string
+	//*reflectutils_test.Variant
+	//[]*reflectutils_test.Variant
+	//*reflectutils_test.Product
+	//*reflectutils_test.Variant
+	//map[string]*reflectutils_test.Variant
+	//<nil>
+	//<nil>
+}
+
 func printJsonV(v interface{}) {
 	j, _ := json.MarshalIndent(v, "", "\t")
 	fmt.Printf("\n\n%s\n", j)
diff --git a/get_type.go b/get_type.go
new file mode 100644
index 0000000..aee5ed5
--- /dev/null
+++ b/get_type.go
@@ -0,0 +1,52 @@
+package reflectutils
+
+import (
+	"reflect"
+	"strings"
+)
+
+// Get value of a struct by path using reflect.
+func GetType(i interface{}, name string) (t reflect.Type) {
+	var err error
+
+	t = reflect.TypeOf(i)
+
+	if name == "" {
+		return
+	}
+
+	var token *dotToken
+	token, err = nextDot(name)
+	if err != nil {
+		return nil
+	}
+
+	if t.Kind() == reflect.Map || t.Kind() == reflect.Slice {
+		t = GetType(reflect.Zero(t.Elem()).Interface(), token.Left)
+		return
+	}
+
+	if t.Kind() != reflect.Struct {
+		for t.Elem().Kind() == reflect.Ptr {
+			t = t.Elem()
+		}
+
+		t = t.Elem()
+	}
+
+	if t.Kind() == reflect.Struct {
+
+		sf, ok := t.FieldByNameFunc(func(name string) bool {
+			return strings.EqualFold(name, token.Field)
+		})
+
+		if !ok {
+			return nil
+		}
+
+		t = GetType(reflect.Zero(sf.Type).Interface(), token.Left)
+		return
+	}
+
+	return
+}