fixed async queue swallowing errors

Author: carlsverre

README.md

@@ -37,6 +37,13 @@ If you are interested in using or contributing to SQLSync, please [join the Disc
 
 Please refer to [the guide](./GUIDE.md) to learn how to add SQLSync to your application.
 
+## Tips & Tricks
+
+### How to debug SQLSync in the browser
+By default SQLSync runs in a shared web worker. This allows the database to automatically be shared between different tabs, however results in making SQLSync a bit harder to debug.
+
+The easiest way is to use Google Chrome, and go to the special URL: [chrome://inspect/#workers](chrome://inspect/#workers). On that page you'll find a list of all the running shared workers in other tabs. Assuming another tab is running SQLSync, you'll see the shared worker listed. Click `inspect` to open up dev-tools for the worker.
+
 ## Community & Contributing
 
 If you are interested in contributing to SQLSync, please [join the Discord community][discord] and let us know what you want to build. All contributions will be held to a high standard, and are more likely to be accepted if they are tied to an existing task and agreed upon specification.

lib/sqlsync-worker/sqlsync-wasm/src/utils.rs

@@ -137,7 +137,8 @@ pub async fn fetch_reducer(reducer_url: &str) -> Result<(WasmReducer, Vec<u8>),
         Uint8Array::new(&digest).to_vec()
     };
 
-    let reducer = WasmReducer::new(reducer_wasm_bytes.as_slice())?;
+    let reducer = WasmReducer::new(reducer_wasm_bytes.as_slice())
+        .map_err(|err| anyhow!("failed to instantiate reducer from wasm: {}", err))?;
 
     Ok((reducer, digest))
 }

lib/sqlsync-worker/src/worker.ts

@@ -19,13 +19,14 @@ const MessageQueue = (() => {
   let queue = Promise.resolve();
   return {
     push: (m: Message) => {
-      queue = queue.then(
-        () => handleMessage(m),
-        (e) => {
+      queue = queue.then(async () => {
+        try {
+          await handleMessage(m);
+        } catch (e) {
           const err = e instanceof Error ? e.message : `error: ${JSON.stringify(e)}`;
           reply(m.portId, m.req.handlerId, { tag: "Err", err });
-        },
-      );
+        }
+      });
     },
   };
 })();