1 files changed, 2 insertions, 2 deletions
diff --git a/packages/pipeline/src/data_sources/web3/index.ts b/packages/pipeline/src/data_sources/web3/index.ts
index 64e909939..45a9ea161 100644
--- a/packages/pipeline/src/data_sources/web3/index.ts
+++ b/packages/pipeline/src/data_sources/web3/index.ts
@@ -3,7 +3,7 @@ import { Web3Wrapper } from '@0x/web3-wrapper';
 import { BlockWithoutTransactionData, Transaction } from 'ethereum-types';
 
 export class Web3Source {
-    private _web3Wrapper: Web3Wrapper;
+    private readonly _web3Wrapper: Web3Wrapper;
     constructor(provider: Web3ProviderEngine) {
         this._web3Wrapper = new Web3Wrapper(provider);
     }
@@ -11,7 +11,7 @@ export class Web3Source {
     public async getBlockInfoAsync(blockNumber: number): Promise<BlockWithoutTransactionData> {
         const block = await this._web3Wrapper.getBlockIfExistsAsync(blockNumber);
         if (block == null) {
-            return Promise.reject(new Error('Could not find block for given block number: ' + blockNumber));
+            return Promise.reject(new Error(`Could not find block for given block number: ${blockNumber}`));
         }
         return block;
     }