feat: complete async api

scripts/build-package.sh

@@ -32,11 +32,10 @@ $WASM_2_JS $OPT --output $ASM
 # WASM2JS only supports generation of es6
 # Whereas node environments require es5 or cjs
 # Hence the folloing converts the import and export syntax
-sed -i -e '/import {/d' $ASM
-sed -i -e '/export var /d' $ASM
-sed -i -e 's/{abort.*},memasmFunc/wbg, memasmFunc/g' $ASM
-sed -i -e 's/var retasmFunc = /module.exports = (wbg) => /' $ASM
-
+sed -i -e 's/import {/\/\/ import {/g' $ASM
+sed -i -e 's/function asmFunc/var bbs = require('\''\.\/wasm'\''); function asmFunc/g' $ASM
+sed -i -e 's/{abort.*},memasmFunc/bbs, memasmFunc/g' $ASM
+sed -i -e 's/export var /module\.exports\./g' $ASM
 # Copy over package sources
 cp -r src/js/* lib/
 
@@ -55,7 +54,13 @@ sed -i -e 's/wasm = wasmInstance/\/\/ wasm = wasmInstance/g' $SRC_WASM
 # Replace with a helper function that support loading the asm.js
 # version as a fall back
 echo "
-wasm = require('./wasm_helper')();
+const createPromise = require('./wasm_helper');
+const wasmPromise = createPromise().catch(() => null);
+
+module.exports.isReady = function () { return !!wasm; }
+module.exports.waitReady = function () { return wasmPromise.then(() => !!wasm); }
+
+wasmPromise.then((_wasm) => { wasm = _wasm });
 " >> $SRC_WASM
 
 # Delete the gitignore and readme automatically created by wasm-pack

src/js/index.js

@@ -54,6 +54,7 @@ if (useWasm) {
   module.exports.BBS_SIGNATURE_LENGTH = 112;
 
   module.exports.generateBls12381G1KeyPair = async (seed) => {
+    await wasm.waitReady();
     var result = await throwErrorOnRejectedPromise(
       wasm.generateBls12381G1KeyPair(seed ? seed : null)
     );
@@ -64,6 +65,7 @@ if (useWasm) {
   };
 
   module.exports.generateBls12381G2KeyPair = async (seed) => {
+    await wasm.waitReady();
     var result = await throwErrorOnRejectedPromise(
       wasm.generateBls12381G2KeyPair(seed ? seed : null)
     );
@@ -74,6 +76,7 @@ if (useWasm) {
   };
 
   module.exports.bls12381toBbs = async (request) => {
+    await wasm.waitReady();
     var result = await throwErrorOnRejectedPromise(wasm.bls12381toBbs(request));
     return {
       publicKey: new Uint8Array(result.publicKey),
@@ -84,27 +87,43 @@ if (useWasm) {
     };
   };
 
-  module.exports.sign = (request) =>
-    throwErrorOnRejectedPromise(wasm.sign(request));
+  module.exports.sign = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.sign(request));
+  };
 
-  module.exports.blsSign = (request) =>
-    throwErrorOnRejectedPromise(wasm.blsSign(request));
+  module.exports.blsSign = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.blsSign(request));
+  };
 
-  module.exports.verify = (request) =>
-    throwErrorOnRejectedPromise(wasm.verify(request));
+  module.exports.verify = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.verify(request));
+  };
 
-  module.exports.blsVerify = (request) =>
-    throwErrorOnRejectedPromise(wasm.blsVerify(request));
+  module.exports.blsVerify = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.blsVerify(request));
+  };
 
-  module.exports.createProof = (request) =>
-    throwErrorOnRejectedPromise(wasm.createProof(request));
+  module.exports.createProof = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.createProof(request));
+  };
 
-  module.exports.blsCreateProof = (request) =>
-    throwErrorOnRejectedPromise(wasm.blsCreateProof(request));
+  module.exports.blsCreateProof = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.blsCreateProof(request));
+  };
 
-  module.exports.verifyProof = (request) =>
-    throwErrorOnRejectedPromise(wasm.verifyProof(request));
+  module.exports.verifyProof = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.verifyProof(request));
+  };
 
-  module.exports.blsVerifyProof = (request) =>
-    throwErrorOnRejectedPromise(wasm.blsVerifyProof(request));
+  module.exports.blsVerifyProof = async (request) => {
+    await wasm.waitReady();
+    return await throwErrorOnRejectedPromise(wasm.blsVerifyProof(request));
+  };
 }

src/js/wasm_helper.js

@@ -21,7 +21,7 @@ const {
   BBS_SIGNATURES_MODES,
 } = require("./util");
 
-module.exports = function getWasmInstance() {
+module.exports = async function () {
   if (
     !process.env.BBS_SIGNATURES_MODE ||
     process.env.BBS_SIGNATURES_MODE !== BBS_SIGNATURES_MODES.asmjs
@@ -30,10 +30,11 @@ module.exports = function getWasmInstance() {
       if (!WebAssembly) {
         throw new Error(WEB_ASSEMBLY_NOT_FOUND_ERROR);
       }
-      const wasmModule = new WebAssembly.Module(bytes);
-      return new WebAssembly.Instance(wasmModule, {
-        __wbindgen_placeholder__: imports,
-      }).exports;
+      return (
+        await WebAssembly.instantiate(bytes, {
+          __wbindgen_placeholder__: imports,
+        })
+      ).instance.exports;
     } catch (error) {
       console.log(
         "The following error occurred in attempting to load the WASM. Attempting to use ASM fallback."
@@ -43,10 +44,9 @@ module.exports = function getWasmInstance() {
   }
 
   // if we have a valid supplied asm.js, return that
-  if (asm()) {
-    return asm();
+  if (asm) {
+    return asm;
   }
-
   console.error(FAILED_INITIALIZE_ERROR);
   console.error(error);