add mut

serde-json-test/src/main.rs

@@ -39,7 +39,7 @@ fn main() -> Result<()> {
     let v: Value = serde_json::from_str(data)?;
     println!("{}", v);
 
-    let john = json!({
+    let mut john = json!({
         "name": "John Doe",
         "age": 43,
         "phones": [
@@ -47,6 +47,12 @@ fn main() -> Result<()> {
             "+44 2345678"
         ]
     });
+    println!("{}", &john);
+
+    if let Option::Some(ref mut m) = john.as_object_mut() {
+        m.insert("test".into(), Value::Bool(true));
+        m.insert("test2".into(), Value::String("hello world".into()));
+    }
     println!("{}", john);
 
     Ok(())