2 files changed, 9 insertions, 2 deletions
diff --git a/src/contract_wrappers/contract_wrapper.ts b/src/contract_wrappers/contract_wrapper.ts
index 925537173..0b65445c1 100644
--- a/src/contract_wrappers/contract_wrapper.ts
+++ b/src/contract_wrappers/contract_wrapper.ts
@@ -13,6 +13,7 @@ import {
     SubscriptionOpts,
     IndexedFilterValues,
     EventCallback,
+    BlockParamLiteral,
 } from '../types';
 import {constants} from '../utils/constants';
 import {intervalUtils} from '../utils/interval_utils';
@@ -120,7 +121,7 @@ export class ContractWrapper {
         delete this._blockAndLogStreamer;
     }
     private async _reconcileBlockAsync(): Promise<void> {
-        const latestBlock = await this._web3Wrapper.getBlockAsync('latest');
+        const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
         // We need to coerce to Block type cause Web3.Block includes types for mempool bloks
         (this._blockAndLogStreamer as BlockAndLogStreamer).reconcileNewBlock(latestBlock as any as Block);
     }
diff --git a/src/types.ts b/src/types.ts
index f0f37bfca..44094f442 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -345,7 +345,13 @@ export interface IndexedFilterValues {
     [index: string]: ContractEventArg;
 }
 
-export type BlockParam = 'latest'|'earliest'|'pending'|number;
+export enum BlockParamLiteral {
+    Latest = 'latest',
+    Earliest = 'earliest',
+    Pending = 'pending',
+}
+
+export type BlockParam = BlockParamLiteral|number;
 
 export interface SubscriptionOpts {
     fromBlock: BlockParam;