Create util mod with `bufToHex` that includes 0x prefix

As this is how the string is represented for Community id.

packages/status-communities/src/identity.ts

@@ -2,9 +2,10 @@ import { Buffer } from "buffer";
 
 import { keccak256 } from "js-sha3";
 import { generatePrivateKey } from "js-waku";
-import { utils } from "js-waku";
 import * as secp256k1 from "secp256k1";
 
+import { hexToBuf } from "./utils";
+
 export class Identity {
   public constructor(public privateKey: Uint8Array) {}
 
@@ -20,7 +21,7 @@ export class Identity {
     const hash = keccak256(payload);
 
     const { signature, recid } = secp256k1.ecdsaSign(
-      utils.hexToBuf(hash),
+      hexToBuf(hash),
       this.privateKey
     );
 

packages/status-communities/src/messenger.spec.ts

@@ -1,9 +1,9 @@
 import { expect } from "chai";
 import debug from "debug";
-import { utils } from "js-waku";
 
 import { Identity } from "./identity";
 import { Messenger } from "./messenger";
+import { bufToHex } from "./utils";
 import { ApplicationMetadataMessage } from "./wire/application_metadata_message";
 import { ContentType } from "./wire/chat_message";
 
@@ -106,8 +106,8 @@ describe("Messenger", () => {
 
     const receivedMessage = await receivedMessagePromise;
 
-    expect(utils.bufToHex(receivedMessage.signer!)).to.eq(
+    expect(bufToHex(receivedMessage.signer!)).to.eq(
-      utils.bufToHex(identityAlice.publicKey)
+      bufToHex(identityAlice.publicKey)
     );
   });
 

packages/status-communities/src/utils.ts

@@ -0,0 +1,11 @@
+import { utils } from "js-waku";
+
+const hexToBuf = utils.hexToBuf;
+export { hexToBuf };
+
+/**
+ * Return hex string with 0x prefix (commonly used for string format of a community id/public key.
+ */
+export function bufToHex(buf: Uint8Array): string {
+  return "0x" + utils.bufToHex(buf);
+}

packages/status-communities/src/wire/application_metadata_message.ts

@@ -1,11 +1,11 @@
 import { keccak256 } from "js-sha3";
-import { utils } from "js-waku";
 import { Reader } from "protobufjs";
 import secp256k1 from "secp256k1";
 
 import { Identity } from "../identity";
 import * as proto from "../proto/status/v1/application_metadata_message";
 import { ApplicationMetadataMessage_Type } from "../proto/status/v1/application_metadata_message";
+import { hexToBuf } from "../utils";
 
 import { ChatMessage } from "./chat_message";
 
@@ -70,6 +70,6 @@ export class ApplicationMetadataMessage {
     const recid = this.signature.slice(64)[0];
     const hash = keccak256(this.payload);
 
-    return secp256k1.ecdsaRecover(signature, recid, utils.hexToBuf(hash));
+    return secp256k1.ecdsaRecover(signature, recid, hexToBuf(hash));
   }
 }