From 7f76672a40e4f606d98e136b70374226faed4cba Mon Sep 17 00:00:00 2001
From: dapplion <guillem.lion.benosa@gmail.com>
Date: Thu, 3 Dec 2020 00:06:36 +0000
Subject: [PATCH] Use browser friendly concatUint8Arrays instead of
 Buffer.concat

---
 src/helpers/utils.ts            | 14 ++++++++++++++
 src/herumi/signature.ts         |  5 ++---
 test/unit/helpers/bytes.test.ts | 25 ++++++++++++++++++++-----
 test/unit/helpers/hex.test.ts   |  5 +----
 4 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/src/helpers/utils.ts b/src/helpers/utils.ts
index 114ab7b..76eae27 100644
--- a/src/helpers/utils.ts
+++ b/src/helpers/utils.ts
@@ -20,3 +20,17 @@ export function validateBytes(
 export function isZeroUint8Array(bytes: Uint8Array): boolean {
   return bytes.every((byte) => byte === 0);
 }
+
+export function concatUint8Arrays(bytesArr: Uint8Array[]): Uint8Array {
+  const totalLen = bytesArr.reduce((total, bytes) => total + bytes.length, 0);
+
+  const merged = new Uint8Array(totalLen);
+  let mergedLen = 0;
+
+  for (const bytes of bytesArr) {
+    merged.set(bytes, mergedLen);
+    mergedLen += bytes.length;
+  }
+
+  return merged;
+}
diff --git a/src/herumi/signature.ts b/src/herumi/signature.ts
index cca6857..e8c41be 100644
--- a/src/herumi/signature.ts
+++ b/src/herumi/signature.ts
@@ -2,7 +2,7 @@ import {SIGNATURE_LENGTH} from "../constants";
 import {SignatureType, multiVerify} from "bls-eth-wasm";
 import {getContext} from "./context";
 import {PublicKey} from "./publicKey";
-import {bytesToHex, hexToBytes, isZeroUint8Array} from "../helpers";
+import {bytesToHex, concatUint8Arrays, hexToBytes, isZeroUint8Array} from "../helpers";
 import {Signature as ISignature} from "../interface";
 import {EmptyAggregateError, InvalidLengthError, InvalidOrderError} from "../errors";
 
@@ -65,10 +65,9 @@ export class Signature implements ISignature {
   }
 
   verifyMultiple(publicKeys: PublicKey[], messages: Uint8Array[]): boolean {
-    const msgs = Buffer.concat(messages);
     return this.value.aggregateVerifyNoCheck(
       publicKeys.map((key) => key.value),
-      msgs
+      concatUint8Arrays(messages)
     );
   }
 
diff --git a/test/unit/helpers/bytes.test.ts b/test/unit/helpers/bytes.test.ts
index 2b14df7..952aaa5 100644
--- a/test/unit/helpers/bytes.test.ts
+++ b/test/unit/helpers/bytes.test.ts
@@ -1,5 +1,6 @@
 import {expect} from "chai";
-import {isZeroUint8Array} from "../../../src/helpers/utils";
+import {concatUint8Arrays, isZeroUint8Array} from "../../../src/helpers/utils";
+import {hexToBytesNode} from "../../util";
 
 describe("helpers / bytes", () => {
   describe("isZeroUint8Array", () => {
@@ -21,8 +22,22 @@ describe("helpers / bytes", () => {
       });
     }
   });
-});
 
-function hexToBytesNode(hex: string): Buffer {
-  return Buffer.from(hex.replace("0x", ""), "hex");
-}
+  describe("concatUint8Arrays", () => {
+    it("Should merge multiple Uint8Array", () => {
+      const bytesArr = [
+        new Uint8Array([1, 2, 3]),
+        new Uint8Array([4, 5]),
+        new Uint8Array([6]),
+        new Uint8Array([7, 8]),
+        new Uint8Array([9, 10, 11]),
+      ];
+
+      const expectedBytes = new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]);
+
+      const bytes = concatUint8Arrays(bytesArr);
+
+      expect(bytes.toString()).to.equal(expectedBytes.toString());
+    });
+  });
+});
diff --git a/test/unit/helpers/hex.test.ts b/test/unit/helpers/hex.test.ts
index 93d5c09..cca61a3 100644
--- a/test/unit/helpers/hex.test.ts
+++ b/test/unit/helpers/hex.test.ts
@@ -1,5 +1,6 @@
 import {expect} from "chai";
 import {hexToBytes, bytesToHex} from "../../../src/helpers/hex";
+import {hexToBytesNode} from "../../util";
 
 describe("helpers / hex", () => {
   const testCases: {id: string; hex: string}[] = [
@@ -23,7 +24,3 @@ describe("helpers / hex", () => {
     });
   }
 });
-
-function hexToBytesNode(hex: string): Buffer {
-  return Buffer.from(hex.replace("0x", ""), "hex");
-}