fux

src/services/web/index.js

@@ -565,6 +565,51 @@ function getZXingReaderWasmUrl() {
   return "./" + ZXING_READER_WASM_PATH;
 }
 
+let cachedWasmBytes = null;
+let cachedWasmBytesUrl = "";
+
+function fetchWasmArrayBuffer(wasmUrl) {
+  if (cachedWasmBytes && cachedWasmBytesUrl === wasmUrl) {
+    return Promise.resolve(cachedWasmBytes);
+  }
+  return fetch(wasmUrl, { credentials: "same-origin" }).then((response) => {
+    if (!response || typeof response.arrayBuffer !== "function") {
+      throw new Error("wasm fetch response is invalid");
+    }
+    if (!response.ok) {
+      throw new Error(`wasm fetch failed: ${response.status}`);
+    }
+    return response.arrayBuffer();
+  }).then((bytes) => {
+    cachedWasmBytes = bytes;
+    cachedWasmBytesUrl = wasmUrl;
+    return bytes;
+  });
+}
+
+function createZxingWasmOverrides() {
+  const wasmUrl = getZXingReaderWasmUrl();
+  return {
+    locateFile(path) {
+      if (path && path.indexOf(".wasm") !== -1) {
+        return wasmUrl;
+      }
+      return path;
+    },
+    instantiateWasm(imports, receiveInstance) {
+      fetchWasmArrayBuffer(wasmUrl).then((bytes) => {
+        return WebAssembly.instantiate(bytes, imports);
+      }).then((result) => {
+        receiveInstance(result.instance, result.module);
+      }).catch((err) => {
+        printWarn("wasm instantiate failed:", err, "url:", wasmUrl);
+        throw err;
+      });
+      return {};
+    },
+  };
+}
+
 function prepareBarcodeDetectorWithTimeout(options) {
   return promiseWithTimeout(
     prepareBarcodeDetector(options),
@@ -582,14 +627,7 @@ function prepareBarcodeDetector(options) {
   if (!barcodeDetectorPreparePromise || options.forcePonyfill) {
     const preparePromise = prepareZXingModule({
       fireImmediately: true,
-      overrides: {
-        locateFile: path => {
-          if (path && path.indexOf(".wasm") !== -1) {
-            return getZXingReaderWasmUrl();
-          }
-          return path;
-        }
-      }
+      overrides: createZxingWasmOverrides(),
     }).then(() => BarcodeDetectorPonyfill).catch(err => {
       if (!options.forcePonyfill) {
         barcodeDetectorPreparePromise = null;