Add error for invalid kv bindings

example/worker/worker.js

@@ -1,20 +1,27 @@
-addEventListener('fetch', event => {
-    event.respondWith(handleRequest(event.request))
-})
+addEventListener("fetch", (event) => {
+    event.respondWith(handleRequest(event.request));
+});
 
 /**
  * Fetch and log a request
  * @param {Request} request
  */
 async function handleRequest() {
-    const { start } = wasm_bindgen
-    await wasm_bindgen(wasm)
-    const text = await start()
+    const { start } = wasm_bindgen;
+    await wasm_bindgen(wasm);
 
-    return new Response(text, {
-        status: 200,
-        headers: {
-            "Content-type": "application/json"
-        }
-    })
+    try {
+        const text = await start();
+
+        return new Response(text, {
+            status: 200,
+            headers: {
+                "Content-type": "application/json",
+            },
+        });
+    } catch (error) {
+        return new Response(error, {
+            status: 500,
+        });
+    }
 }

src/lib.rs

@@ -40,15 +40,21 @@ pub struct KvStore {
 impl KvStore {
     /// Creates a new [`KvStore`] with the binding specified in your `wrangler.toml`.
     pub fn create(binding: &str) -> Result<Self, KvError> {
-        let this: Object = get(&global(), binding.as_ref())?.into();
-        Ok(Self {
-            get_function: get(&this, "get")?.into(),
-            get_with_meta_function: get(&this, "getWithMetadata")?.into(),
-            put_function: get(&this, "put")?.into(),
-            list_function: get(&this, "list")?.into(),
-            delete_function: get(&this, "delete")?.into(),
-            this,
-        })
+        let this = get(&global(), binding.as_ref())?;
+
+        // Ensures that the kv store exists.
+        if this.is_undefined() {
+            Err(KvError::InvalidKvStore(binding.into()))
+        } else {
+            Ok(Self {
+                get_function: get(&this, "get")?.into(),
+                get_with_meta_function: get(&this, "getWithMetadata")?.into(),
+                put_function: get(&this, "put")?.into(),
+                list_function: get(&this, "list")?.into(),
+                delete_function: get(&this, "delete")?.into(),
+                this: this.into(),
+            })
+        }
     }
 
     /// Fetches the value from the kv store by name.
@@ -160,13 +166,15 @@ pub struct Key {
 pub enum KvError {
     JavaScript(JsValue),
     Serialization(serde_json::Error),
+    InvalidKvStore(String),
 }
 
 impl Into<JsValue> for KvError {
     fn into(self) -> JsValue {
         match self {
             Self::JavaScript(value) => value,
             Self::Serialization(e) => format!("KvError::Serialization: {}", e.to_string()).into(),
+            Self::InvalidKvStore(binding) => format!("KvError::InvalidKvStore: {}", binding).into(),
         }
     }
 }