1 files changed, 23 insertions, 0 deletions
diff --git a/src/value_ext.rs b/src/value_ext.rs
new file mode 100644
index 0000000..71b4175
--- /dev/null
+++ b/src/value_ext.rs
@@ -0,0 +1,23 @@
+use crate::error::{Error, Result};
+use serde_json::Value;
+
+/// Some extensions for serde_json::Value to be used as TDLib object
+pub trait ValueExt {
+    /// get @type from json
+    fn get_type<'a>(&'a self) -> Result<&'a str>;
+
+    /// get @extra from json
+    fn get_extra<'a>(&'a self) -> Result<&'a str>;
+}
+
+impl ValueExt for Value {
+    fn get_type<'a>(&'a self) -> Result<&'a str> {
+        self["@type"].as_str().ok_or(Error::HasNoTypeInJson)
+    }
+
+    fn get_extra<'a>(&'a self) -> Result<&'a str> {
+        self["@extra"]
+            .as_str()
+            .ok_or_else(|| Error::InvalidJson("no @extra in json".into()))
+    }
+}