Update examples with metadta
diff --git a/mapstructure_examples_test.go b/mapstructure_examples_test.go
index 0e1af6b..7eaba0d 100644
--- a/mapstructure_examples_test.go
+++ b/mapstructure_examples_test.go
@@ -68,3 +68,39 @@
// * 'Emails[1]' expected type 'string', got 'int'
// * 'Emails[2]' expected type 'string', got 'int'
}
+
+func ExampleDecode_metadata() {
+ type Person struct {
+ Name string
+ Age int
+ }
+
+ // This input can come from anywhere, but typically comes from
+ // something like decoding JSON where we're not quite sure of the
+ // struct initially.
+ input := map[string]interface{}{
+ "name": "Mitchell",
+ "age": 91,
+ "email": "foo@bar.com",
+ }
+
+ var md Metadata
+ var result Person
+ config := &DecoderConfig{
+ Metadata: &md,
+ Result: &result,
+ }
+
+ decoder, err := NewDecoder(config)
+ if err != nil {
+ panic(err)
+ }
+
+ if err := decoder.Decode(input); err != nil {
+ panic(err)
+ }
+
+ fmt.Printf("Unused keys: %#v", md.Unused)
+ // Output:
+ // Unused keys: []string{"email"}
+}
