fix: incorrect variable access (#6862)

packages/beacon-node/src/network/gossip/encoding.ts

@@ -3,6 +3,7 @@ import xxhashFactory from "xxhash-wasm";
 import {Message} from "@libp2p/interface";
 import {digest} from "@chainsafe/as-sha256";
 import {RPC} from "@chainsafe/libp2p-gossipsub/message";
+import {DataTransform} from "@chainsafe/libp2p-gossipsub/types";
 import {intToBytes, toHex} from "@lodestar/utils";
 import {ForkName} from "@lodestar/params";
 import {MESSAGE_DOMAIN_VALID_SNAPPY} from "./constants.js";
@@ -61,7 +62,7 @@ export function msgIdFn(gossipTopicCache: GossipTopicCache, msg: Message): Uint8
   return digest(Buffer.concat(vec)).subarray(0, 20);
 }
 
-export class DataTransformSnappy {
+export class DataTransformSnappy implements DataTransform {
   constructor(
     private readonly gossipTopicCache: GossipTopicCache,
     private readonly maxSizePerMessage: number
@@ -96,9 +97,9 @@ export class DataTransformSnappy {
    * Takes the data to be published (a topic and associated data) transforms the data. The
    * transformed data will then be used to create a `RawGossipsubMessage` to be sent to peers.
    */
-  outboundTransform(topicStr: string, data: Uint8Array): Uint8Array {
+  outboundTransform(_topicStr: string, data: Uint8Array): Uint8Array {
     if (data.length > this.maxSizePerMessage) {
-      throw Error(`ssz_snappy encoded data length ${length} > ${this.maxSizePerMessage}`);
+      throw Error(`ssz_snappy encoded data length ${data.length} > ${this.maxSizePerMessage}`);
     }
     // No need to parse topic, everything is snappy compressed
     return compress(data);