walk: check if the field is of string type

walk/walk.go

@@ -7,6 +7,8 @@ import (
 func Walk(x interface{}, fn func(string)) {
 	val := reflect.ValueOf(x)
 	for i := 0; i < val.NumField(); i++ {
+		if val.Field(i).Kind() == reflect.String {
 			fn(val.Field(i).String())
 		}
+	}
 }

walk/walk_test.go

@@ -26,6 +26,14 @@ func TestWalk(t *testing.T) {
 			}{"Chris", "London"},
 			[]string{"Chris", "London"},
 		},
+		{
+			"struct with non string field",
+			struct {
+				Name string
+				Age  int
+			}{"Chris", 29},
+			[]string{"Chris"},
+		},
 	}
 
 	for _, test := range cases {