From 3ef01dbd081d28603438202501867a8f9806629a Mon Sep 17 00:00:00 2001
From: Alex Victoor <alexvictoor@gmail.com>
Date: Tue, 21 Jul 2020 21:53:00 +0200
Subject: [PATCH] Synchronous WASM init

---
 README.md             | 7 ++++++-
 src/Histogram.spec.ts | 4 ++--
 src/index.ts          | 3 ++-
 src/wasm/index.ts     | 5 +++++
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index ea3a2f7..e967c5f 100644
--- a/README.md
+++ b/README.md
@@ -198,9 +198,14 @@ The code fragment below shows how to instantiate a resizable 32 bits WebAssembly
 ```
 import * as hdr from "hdr-histogram-js"
 
-// load HdrHistogramJS WASM module
+// If you are on the browser side, you need to
+// load asynchronously HdrHistogramJS WASM module
 await hdr.initWebAssembly();
 
+// If you are on the server side, you can
+// load synchronously HdrHistogramJS WASM module
+hdr.initWebAssemblySync();
+
 const histogram = hdr.build({ useWebAssembly: true });
 
 // you can now use your histogram the same way you would do
diff --git a/src/Histogram.spec.ts b/src/Histogram.spec.ts
index 92cf9ab..00a89e1 100644
--- a/src/Histogram.spec.ts
+++ b/src/Histogram.spec.ts
@@ -2,7 +2,7 @@ import { build } from ".";
 import JsHistogram from "./JsHistogram";
 import { NO_TAG } from "./Histogram";
 import Int32Histogram from "./Int32Histogram";
-import { initWebAssembly, WasmHistogram } from "./wasm";
+import { initWebAssembly, WasmHistogram, initWebAssemblySync } from "./wasm";
 import Int8Histogram from "./Int8Histogram";
 import Histogram from "./Histogram";
 
@@ -309,7 +309,7 @@ describe("WASM Histogram not initialized", () => {
 });
 
 describe("WASM Histogram not happy path", () => {
-  beforeEach(initWebAssembly);
+  beforeEach(initWebAssemblySync);
   it("should throw a clear error message when used after destroy", () => {
     const destroyedHistogram = build({ useWebAssembly: true });
     destroyedHistogram.destroy();
diff --git a/src/index.ts b/src/index.ts
index 1d958e3..ad40a6d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -19,11 +19,12 @@ import Int8Histogram from "./Int8Histogram";
 import JsHistogram from "./JsHistogram";
 import PackedHistogram from "./PackedHistogram";
 import Recorder from "./Recorder";
-import { initWebAssembly, WasmHistogram } from "./wasm";
+import { initWebAssembly, initWebAssemblySync, WasmHistogram } from "./wasm";
 import { build } from "./HistogramBuilder";
 
 export {
   initWebAssembly,
+  initWebAssemblySync,
   Int8Histogram,
   Int16Histogram,
   Int32Histogram,
diff --git a/src/wasm/index.ts b/src/wasm/index.ts
index ef66efd..2e4dc5a 100644
--- a/src/wasm/index.ts
+++ b/src/wasm/index.ts
@@ -43,6 +43,11 @@ export const initWebAssembly = async (): Promise<void> => {
     .then((w: any) => (wasm = w.exports || w));
 };
 
+export const initWebAssemblySync = () => {
+  const w = loader.instantiateSync(pako.inflate(base64.toByteArray(BINARY)));
+  wasm = w.exports || w;
+};
+
 export const webAssemblyReady = () => !!wasm;
 
 const defaultRequest: BuildRequest = {