1 files changed, 15 insertions, 4 deletions
diff --git a/src/contract_wrappers/token_registry_wrapper.ts b/src/contract_wrappers/token_registry_wrapper.ts
index 4d6eacb51..86bea1c5d 100644
--- a/src/contract_wrappers/token_registry_wrapper.ts
+++ b/src/contract_wrappers/token_registry_wrapper.ts
@@ -1,20 +1,23 @@
 import * as _ from 'lodash';
 import {Web3Wrapper} from '../web3_wrapper';
-import {ZeroExError, Token, TokenRegistryContract} from '../types';
+import {Token, TokenRegistryContract, TokenMetadata} from '../types';
 import {assert} from '../utils/assert';
 import {ContractWrapper} from './contract_wrapper';
 import * as TokenRegistryArtifacts from '../artifacts/TokenRegistry.json';
 
 export class TokenRegistryWrapper extends ContractWrapper {
+    private tokenRegistryContractIfExists?: TokenRegistryContract;
     constructor(web3Wrapper: Web3Wrapper) {
         super(web3Wrapper);
     }
+    public invalidateContractInstance(): void {
+        delete this.tokenRegistryContractIfExists;
+    }
     public async getTokensAsync(): Promise<Token[]> {
-        const contractInstance = await this.instantiateContractIfExistsAsync((TokenRegistryArtifacts as any));
-        const tokenRegistryContract = contractInstance as TokenRegistryContract;
+        const tokenRegistryContract = await this.getTokenRegistryContractAsync();
 
         const addresses = await tokenRegistryContract.getTokenAddresses.call();
-        const tokenMetadataPromises: Array<Promise<any[]>> = _.map(
+        const tokenMetadataPromises: Array<Promise<TokenMetadata>> = _.map(
             addresses,
             (address: string) => (tokenRegistryContract.getTokenMetaData.call(address)),
         );
@@ -30,4 +33,12 @@ export class TokenRegistryWrapper extends ContractWrapper {
         });
         return tokens;
     }
+    private async getTokenRegistryContractAsync(): Promise<TokenRegistryContract> {
+        if (!_.isUndefined(this.tokenRegistryContractIfExists)) {
+            return this.tokenRegistryContractIfExists;
+        }
+        const contractInstance = await this.instantiateContractIfExistsAsync((TokenRegistryArtifacts as any));
+        this.tokenRegistryContractIfExists = contractInstance as TokenRegistryContract;
+        return this.tokenRegistryContractIfExists;
+    }
 }