feat: wit-bindgen-sample

__wasm/wit-bindgen-sample/engine/src/lib.rs

@@ -9,15 +9,12 @@ struct Exports;
 impl exports::Exports for Exports {
     fn eval_javascript(script: String) -> String {
         let mut ctx = Context::default();
-        ctx.register_global_function("fetch", 0, fetch_fn);
+        ctx.register_global_function("fetch", 0, do_fetch);
         let o = match ctx.eval(&script) {
             JsResult::Ok(o) => o,
             JsResult::Err(o) => o,
         };
-        format!("{}", o.to_json(&mut ctx).unwrap())
-        // let a = container::fetch("");
-        // let a = fetch_from_host("<CONFIG>");
-        // format!("eval: {}, fetched: {}", s, a)
+        format!("{}", o.to_json(&mut ctx).expect("To JSON error"))
     }
 }
 
@@ -27,14 +24,17 @@ struct FetchResult {
     result: Option<String>,
 }
 
-fn fetch_fn(_: &JsValue, args: &[JsValue], ctx: &mut Context) -> JsResult<JsValue> {
+fn do_fetch(_: &JsValue, args: &[JsValue], ctx: &mut Context) -> JsResult<JsValue> {
+    if args.is_empty() {
+        return JsResult::Err(JsValue::String(JsString::from("Requires at least one argument")));
+    }
     let mut fetch_params_map = Map::new();
     fetch_params_map.insert("url".to_string(), args[0].to_json(ctx).expect("error"));
     if args.len() > 1 {
         fetch_params_map.insert("params".to_string(), args[1].to_json(ctx).expect("error"));
     }
     let fetch_params = format!("{}", Value::Object(fetch_params_map));
-    
+
     let fetch_result_string = container::fetch(&fetch_params);
     let fetch_result: FetchResult = serde_json::from_str(&fetch_result_string).expect("from str error");
     if let Some(result) = fetch_result.result {
@@ -42,5 +42,5 @@ fn fetch_fn(_: &JsValue, args: &[JsValue], ctx: &mut Context) -> JsResult<JsValu
         let v = JsValue::from_json(&r, ctx).unwrap();
         return JsResult::Ok(v);
     }
-    JsResult::Err(JsValue::String(JsString::from(format!("Invoke fetch error: {}", fetch_result.error.unwrap_or("".to_string())))))
+    JsResult::Err(JsValue::String(JsString::from(format!("Invoke fetch error: {}", fetch_result.error.unwrap_or("<unknown>".to_string())))))
 }