Add error to JsValue conversion and example (#691)

src/error.rs

@@ -170,6 +170,20 @@ impl StdError for Error {
     }
 }
 
+#[cfg(target_arch = "wasm32")]
+impl From<crate::error::Error> for wasm_bindgen::JsValue {
+    fn from(err: Error) -> wasm_bindgen::JsValue {
+        js_sys::Error::from(err).into()
+    }
+}
+
+#[cfg(target_arch = "wasm32")]
+impl From<crate::error::Error> for js_sys::Error {
+    fn from(err: Error) -> js_sys::Error {
+        js_sys::Error::new(&format!("{}", err))
+    }
+}
+
 #[derive(Debug)]
 pub(crate) enum Kind {
     Builder,