perf: prewarm wasm

analyze/index.ts

@@ -83,6 +83,17 @@ function createCoreImports(detect?: DetectSensitiveInfoFunction): ImportObject {
   };
 }
 
+/**
+ * Pre-warms the wasm cache to improve cold start performance.
+ * @returns Whether the cache was successfully warmed or not.
+ */
+export async function prewarmWasmCache(): Promise<boolean> {
+  const coreImports = createCoreImports();
+  const analyze = await initializeWasm(coreImports);
+
+  return typeof analyze !== "undefined";
+}
+
 /**
  * Generate a fingerprint for the client. This is used to identify the client
  * across multiple requests.

arcjet/index.ts

@@ -1240,6 +1240,8 @@ export default function arcjet<
   }
   const log = options.log;
 
+  const wasmPrewarm = analyze.prewarmWasmCache();
+
   const perf = new Performance(log);
 
   // TODO(#207): Remove this when we can default the transport so client is not required
@@ -1298,6 +1300,15 @@ export default function arcjet<
       ...ctx,
     };
 
+    const logWasmPrewarmPerf = perf.measure("wasm prewarm");
+    const prewarmed = await wasmPrewarm;
+    if (!prewarmed) {
+      log.debug(
+        "Wasm prewarm failed. This may indicate that Wasm is not supported on this platform",
+      );
+    }
+    logWasmPrewarmPerf();
+
     let fingerprint = "";
 
     const logFingerprintPerf = perf.measure("fingerprint");