1 files changed, 48 insertions, 0 deletions
diff --git a/std/hash/_wasm/build.ts b/std/hash/_wasm/build.ts
new file mode 100644
index 000000000..eaa6a21dd
--- /dev/null
+++ b/std/hash/_wasm/build.ts
@@ -0,0 +1,48 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+import { encode as base64Encode } from "../../encoding/base64.ts";
+
+// 1. build wasm
+async function buildWasm(path: string): Promise<void> {
+  const cmd = [
+    "wasm-pack",
+    "build",
+    "--target",
+    "web",
+    "--release",
+    "-d",
+    path,
+  ];
+  const builder = Deno.run({ cmd });
+  const status = await builder.status();
+
+  if (!status.success) {
+    console.error(`Failed to build wasm: ${status.code}`);
+    Deno.exit(1);
+  }
+}
+
+// 2. encode wasm
+async function encodeWasm(wasmPath: string): Promise<string> {
+  const wasm = await Deno.readFile(`${wasmPath}/deno_hash_bg.wasm`);
+  return base64Encode(wasm);
+}
+
+// 3. generate script
+async function generate(wasm: string, output: string): Promise<void> {
+  const initScript = await Deno.readTextFile(`${output}/deno_hash.js`);
+  const denoHashScript =
+    "/* eslint-disable */\n" +
+    "//deno-fmt-ignore-file\n" +
+    `import * as base64 from "../../encoding/base64.ts";` +
+    `export const source = base64.decode("${wasm}");` +
+    initScript;
+
+  await Deno.writeFile("wasm.js", new TextEncoder().encode(denoHashScript));
+}
+
+const OUTPUT_DIR = "./out";
+
+await buildWasm(OUTPUT_DIR);
+const wasm = await encodeWasm(OUTPUT_DIR);
+await generate(wasm, OUTPUT_DIR);