fix: propagate load errors through wasm

lib/eszip_test.ts

@@ -2,6 +2,7 @@ import { build, Parser } from "./mod.ts";
 import {
   assert,
   assertEquals,
+  assertRejects,
 } from "https://deno.land/std@0.123.0/testing/asserts.ts";
 
 Deno.test("roundtrip build + parse", async () => {
@@ -57,3 +58,15 @@ Deno.test("build default loader", async () => {
   const eszip = await build(["https://deno.land/std@0.123.0/fs/mod.ts"]);
   assert(eszip instanceof Uint8Array);
 });
+
+Deno.test("loader errors", async () => {
+  await assertRejects(
+    () =>
+      build(
+        ["https://deno.land/std@0.123.0/fs/mod.ts"],
+        (specifier: string) => Promise.reject(new Error("oops")),
+      ),
+    undefined,
+    "oops",
+  );
+});

lib/eszip_wasm.generated.js

@@ -24,6 +24,15 @@ function takeObject(idx) {
   return ret;
 }
 
+function addHeapObject(obj) {
+  if (heap_next === heap.length) heap.push(heap.length + 1);
+  const idx = heap_next;
+  heap_next = heap[idx];
+
+  heap[idx] = obj;
+  return idx;
+}
+
 let WASM_VECTOR_LEN = 0;
 
 let cachegetUint8Memory0 = null;
@@ -95,15 +104,6 @@ function getInt32Memory0() {
   return cachegetInt32Memory0;
 }
 
-function addHeapObject(obj) {
-  if (heap_next === heap.length) heap.push(heap.length + 1);
-  const idx = heap_next;
-  heap_next = heap[idx];
-
-  heap[idx] = obj;
-  return idx;
-}
-
 let cachedTextDecoder = new TextDecoder("utf-8", {
   ignoreBOM: true,
   fatal: true,
@@ -241,7 +241,7 @@ function handleError(f, args) {
     wasm.__wbindgen_exn_store(addHeapObject(e));
   }
 }
-function __wbg_adapter_60(arg0, arg1, arg2, arg3) {
+function __wbg_adapter_62(arg0, arg1, arg2, arg3) {
   wasm.wasm_bindgen__convert__closures__invoke2_mut__h7fbd29c1fe4dda8a(
     arg0,
     arg1,
@@ -364,18 +364,6 @@ const imports = {
       var ret = getObject(arg0).toString();
       return addHeapObject(ret);
     },
-    __wbindgen_string_get: function (arg0, arg1) {
-      const obj = getObject(arg1);
-      var ret = typeof (obj) === "string" ? obj : undefined;
-      var ptr0 = isLikeNone(ret) ? 0 : passStringToWasm0(
-        ret,
-        wasm.__wbindgen_malloc,
-        wasm.__wbindgen_realloc,
-      );
-      var len0 = WASM_VECTOR_LEN;
-      getInt32Memory0()[arg0 / 4 + 1] = len0;
-      getInt32Memory0()[arg0 / 4 + 0] = ptr0;
-    },
     __wbg_value_f6f2ef297faa6b4a: function (arg0) {
       var ret = getObject(arg0).value;
       return isLikeNone(ret) ? 0 : addHeapObject(ret);
@@ -420,7 +408,7 @@ const imports = {
           const a = state0.a;
           state0.a = 0;
           try {
-            return __wbg_adapter_60(a, state0.b, arg0, arg1);
+            return __wbg_adapter_62(a, state0.b, arg0, arg1);
           } finally {
             state0.a = a;
           }
@@ -431,6 +419,20 @@ const imports = {
         state0.a = state0.b = 0;
       }
     },
+    __wbindgen_string_get: function (arg0, arg1) {
+      const obj = getObject(arg1);
+      var ret = typeof (obj) === "string" ? obj : undefined;
+      var ptr0 = isLikeNone(ret)
+        ? 0
+        : passStringToWasm0(
+          ret,
+          wasm.__wbindgen_malloc,
+          wasm.__wbindgen_realloc,
+        );
+      var len0 = WASM_VECTOR_LEN;
+      getInt32Memory0()[arg0 / 4 + 1] = len0;
+      getInt32Memory0()[arg0 / 4 + 0] = ptr0;
+    },
     __wbindgen_string_new: function (arg0, arg1) {
       var ret = getStringFromWasm0(arg0, arg1);
       return addHeapObject(ret);
@@ -447,6 +449,10 @@ const imports = {
       getInt32Memory0()[arg0 / 4 + 1] = len0;
       getInt32Memory0()[arg0 / 4 + 0] = ptr0;
     },
+    __wbg_new_55259b13834a484c: function (arg0, arg1) {
+      var ret = new Error(getStringFromWasm0(arg0, arg1));
+      return addHeapObject(ret);
+    },
     __wbg_newwithbyteoffsetandlength_278ec7532799393a: function (
       arg0,
       arg1,
@@ -578,8 +584,8 @@ const imports = {
       var ret = getObject(arg0).then(getObject(arg1));
       return addHeapObject(ret);
     },
-    __wbindgen_closure_wrapper8543: function (arg0, arg1, arg2) {
-      var ret = makeMutClosure(arg0, arg1, 134, __wbg_adapter_24);
+    __wbindgen_closure_wrapper8569: function (arg0, arg1, arg2) {
+      var ret = makeMutClosure(arg0, arg1, 135, __wbg_adapter_24);
       return addHeapObject(ret);
     },
   },

lib/lib.rs

@@ -247,7 +247,7 @@ pub async fn build_eszip(
   std::panic::set_hook(Box::new(console_error_panic_hook::hook));
   let roots: Vec<deno_graph::ModuleSpecifier> = roots
     .into_serde()
-    .map_err(|e| JsValue::from_str(&e.to_string()))?;
+    .map_err(|e| js_sys::Error::new(&e.to_string()))?;
   let mut loader = GraphLoader(loader);
   let graph = deno_graph::create_graph(
     roots
@@ -263,8 +263,11 @@ pub async fn build_eszip(
     None,
   )
   .await;
+  graph
+    .valid()
+    .map_err(|e| js_sys::Error::new(&e.to_string()))?;
   let eszip = eszip::EszipV2::from_graph(graph, Default::default())
-    .map_err(|e| JsValue::from_str(&e.to_string()))?;
+    .map_err(|e| js_sys::Error::new(&e.to_string()))?;
   Ok(Uint8Array::from(eszip.into_bytes().as_slice()))
 }
 
@@ -303,7 +306,11 @@ impl Loader for GraphLoader {
         };
         response
           .map(|value| value.into_serde().unwrap())
-          .map_err(|_| anyhow::anyhow!("load rejected or errored"))
+          .map_err(|err| {
+            anyhow::anyhow!(err
+              .as_string()
+              .unwrap_or_else(|| "an error occured during loading".to_string()))
+          })
       })
     }
   }

lib/mod.ts

@@ -8,5 +8,9 @@ export function build(
   roots: string[],
   loader: (url: string) => Promise<LoadResponse | undefined> = load,
 ): Promise<Uint8Array> {
-  return _build(roots, loader);
+  return _build(
+    roots,
+    (specifier: string) =>
+      loader(specifier).catch((err) => Promise.reject(String(err))),
+  );
 }