feat(retrieve): adding GetOrElse (#78)

README.rst

@@ -372,6 +372,20 @@ Retrieves the value at path of struct(s).
     funk.Get([]*Foo{foo1, foo2}, "Bar.Name") // []string{"Test"}
     funk.Get(foo2, "Bar.Name") // nil
 
+
+
+funk.GetOrElse
+.........
+
+Retrieves the value of the pointer or default.
+
+.. code-block:: go
+    str := "hello world"
+    GetOrElse(&str, "foobar")   // string{"hello world"}
+    GetOrElse(str, "foobar")    // string{"hello world"}
+    GetOrElse(nil, "foobar")    // string{"foobar"}
+
+
 funk.Keys
 .........
 

retrieve.go

@@ -21,11 +21,11 @@ func get(value reflect.Value, path string) reflect.Value {
 		var resultSlice reflect.Value
 
 		length := value.Len()
-		
+
 		if length == 0 {
 			return resultSlice
 		}
-		
+
 		for i := 0; i < length; i++ {
 			item := value.Index(i)
 
@@ -77,3 +77,14 @@ func get(value reflect.Value, path string) reflect.Value {
 
 	return value
 }
+
+// Get retrieves the value of the pointer or default.
+func GetOrElse(v interface{}, def interface{}) interface{} {
+	val := reflect.ValueOf(v)
+	if v == nil {
+		return def
+	} else if val.Kind() != reflect.Ptr {
+		return v
+	}
+	return val.Elem().Interface()
+}

retrieve_test.go

@@ -46,3 +46,12 @@ func TestGetSimple(t *testing.T) {
 
 	is.Equal(result, []string{"Level1-1", "Level1-2"})
 }
+
+func TestGetOrElse(t *testing.T) {
+	is := assert.New(t)
+
+	str := "hello world"
+	is.Equal("hello world", GetOrElse(&str, "foobar"))
+	is.Equal("hello world", GetOrElse(str, "foobar"))
+	is.Equal("foobar", GetOrElse(nil, "foobar"))
+}