Fix unhandled promise rejection error on subscriptions

4 files changed, 38 insertions, 24 deletions

diff --git a/src/contract_wrappers/contract_wrapper.ts b/src/contract_wrappers/contract_wrapper.ts
index 19dccc6f2..a02465982 100644
--- a/src/contract_wrappers/contract_wrapper.ts
+++ b/src/contract_wrappers/contract_wrapper.ts
@@ -50,10 +50,14 @@ export class ContractWrapper {
         this._filterCallbacks[filterToken] = callback;
         return filterToken;
     }
-    protected _unsubscribe(filterToken: string): void {
+    protected _unsubscribe(filterToken: string, err?: Error): void {
         if (_.isUndefined(this._filters[filterToken])) {
             throw new Error(ZeroExError.SubscriptionNotFound);
         }
+        if (!_.isUndefined(err)) {
+            const callback = this._filterCallbacks[filterToken];
+            callback(err, undefined);
+        }
         delete this._filters[filterToken];
         delete this._filterCallbacks[filterToken];
         if (_.isEmpty(this._filters)) {
@@ -90,7 +94,7 @@ export class ContractWrapper {
                     ...decodedLog,
                     removed,
                 };
-                this._filterCallbacks[filterToken](logEvent);
+                this._filterCallbacks[filterToken](null, logEvent);
             }
         });
     }
@@ -122,11 +126,18 @@ export class ContractWrapper {
         delete this._blockAndLogStreamer;
     }
     private async _reconcileBlockAsync(): Promise<void> {
-        const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
-        // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
-        if (!_.isUndefined(this._blockAndLogStreamer)) {
-            // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
-            this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block);
+        try {
+            const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
+            // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
+            if (!_.isUndefined(this._blockAndLogStreamer)) {
+                // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
+                this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block);
+            }
+        } catch (err) {
+            const filterTokens = _.keys(this._filterCallbacks);
+            _.each(filterTokens, filterToken => {
+                this._unsubscribe(filterToken, err);
+            });
         }
     }
 }
diff --git a/src/types.ts b/src/types.ts
index a9eac56d8..af3c36736 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -41,8 +41,8 @@ export type OrderValues = [BigNumber, BigNumber, BigNumber,
 export interface LogEvent<ArgsType> extends LogWithDecodedArgs<ArgsType> {
     removed: boolean;
 }
-export type EventCallbackAsync<ArgsType> = (log: LogEvent<ArgsType>) => Promise<void>;
-export type EventCallbackSync<ArgsType> = (log: LogEvent<ArgsType>) => void;
+export type EventCallbackAsync<ArgsType> = (err: null|Error, log?: LogEvent<ArgsType>) => Promise<void>;
+export type EventCallbackSync<ArgsType> = (err: null|Error, log?: LogEvent<ArgsType>) => void;
 export type EventCallback<ArgsType> = EventCallbackSync<ArgsType>|EventCallbackAsync<ArgsType>;
 export interface ExchangeContract extends Web3.ContractInstance {
     isValidSignature: {
diff --git a/test/exchange_wrapper_test.ts b/test/exchange_wrapper_test.ts
index 7c76499d5..654f626c6 100644
--- a/test/exchange_wrapper_test.ts
+++ b/test/exchange_wrapper_test.ts
@@ -304,11 +304,11 @@ describe('ExchangeWrapper', () => {
                     orderFillBatch = [
                         {
                             signedOrder,
-                            takerTokenFillAmount: takerTokenFillAmount,
+                            takerTokenFillAmount,
                         },
                         {
                             signedOrder: anotherSignedOrder,
-                            takerTokenFillAmount: takerTokenFillAmount,
+                            takerTokenFillAmount,
                         },
                     ];
                 });
@@ -647,7 +647,7 @@ describe('ExchangeWrapper', () => {
         // Source: https://github.com/mochajs/mocha/issues/2407
         it('Should receive the LogFill event when an order is filled', (done: DoneCallback) => {
             (async () => {
-                const callback = (logEvent: LogEvent<LogFillContractEventArgs>) => {
+                const callback = (err: Error, logEvent: LogEvent<LogFillContractEventArgs>) => {
                     expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
                     done();
                 };
@@ -655,13 +655,14 @@ describe('ExchangeWrapper', () => {
                     ExchangeEvents.LogFill, indexFilterValues, callback,
                 );
                 await zeroEx.exchange.fillOrderAsync(
-                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
                 );
             })().catch(done);
         });
         it('Should receive the LogCancel event when an order is cancelled', (done: DoneCallback) => {
             (async () => {
-                const callback = (logEvent: LogEvent<LogCancelContractEventArgs>) => {
+                const callback = (err: Error, logEvent: LogEvent<LogCancelContractEventArgs>) => {
                     expect(logEvent.event).to.be.equal(ExchangeEvents.LogCancel);
                     done();
                 };
@@ -673,7 +674,7 @@ describe('ExchangeWrapper', () => {
         });
         it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (logEvent: LogEvent<LogFillContractEventArgs>) => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: LogEvent<LogFillContractEventArgs>) => {
                     done(new Error('Expected this subscription to have been cancelled'));
                 };
                 await zeroEx.exchange.subscribeAsync(
@@ -683,7 +684,7 @@ describe('ExchangeWrapper', () => {
                 const newProvider = web3Factory.getRpcProvider();
                 await zeroEx.setProviderAsync(newProvider);
 
-                const callback = (logEvent: LogEvent<LogFillContractEventArgs>) => {
+                const callback = (err: Error, logEvent: LogEvent<LogFillContractEventArgs>) => {
                     expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
                     done();
                 };
@@ -691,13 +692,14 @@ describe('ExchangeWrapper', () => {
                     ExchangeEvents.LogFill, indexFilterValues, callback,
                 );
                 await zeroEx.exchange.fillOrderAsync(
-                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
                 );
             })().catch(done);
         });
         it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (logEvent: LogEvent<LogFillContractEventArgs>) => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: LogEvent<LogFillContractEventArgs>) => {
                     done(new Error('Expected this subscription to have been cancelled'));
                 };
                 const subscriptionToken = await zeroEx.exchange.subscribeAsync(
@@ -705,7 +707,8 @@ describe('ExchangeWrapper', () => {
                 );
                 zeroEx.exchange.unsubscribe(subscriptionToken);
                 await zeroEx.exchange.fillOrderAsync(
-                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
                 );
                 done();
             })().catch(done);
diff --git a/test/token_wrapper_test.ts b/test/token_wrapper_test.ts
index b35fa43f9..b244e3a92 100644
--- a/test/token_wrapper_test.ts
+++ b/test/token_wrapper_test.ts
@@ -358,7 +358,7 @@ describe('TokenWrapper', () => {
         // Source: https://github.com/mochajs/mocha/issues/2407
         it('Should receive the Transfer event when tokens are transfered', (done: DoneCallback) => {
             (async () => {
-                const callback = (logEvent: LogEvent<TransferContractEventArgs>) => {
+                const callback = (err: Error, logEvent: LogEvent<TransferContractEventArgs>) => {
                     expect(logEvent).to.not.be.undefined();
                     const args = logEvent.args;
                     expect(args._from).to.be.equal(coinbase);
@@ -373,7 +373,7 @@ describe('TokenWrapper', () => {
         });
         it('Should receive the Approval event when allowance is being set', (done: DoneCallback) => {
             (async () => {
-                const callback = (logEvent: LogEvent<ApprovalContractEventArgs>) => {
+                const callback = (err: Error, logEvent: LogEvent<ApprovalContractEventArgs>) => {
                     expect(logEvent).to.not.be.undefined();
                     const args = logEvent.args;
                     expect(args._owner).to.be.equal(coinbase);
@@ -388,13 +388,13 @@ describe('TokenWrapper', () => {
         });
         it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (logEvent: LogEvent<TransferContractEventArgs>) => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: LogEvent<TransferContractEventArgs>) => {
                     done(new Error('Expected this subscription to have been cancelled'));
                 };
                 zeroEx.token.subscribe(
                     tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled,
                 );
-                const callbackToBeCalled = (logEvent: LogEvent<TransferContractEventArgs>) => {
+                const callbackToBeCalled = (err: Error, logEvent: LogEvent<TransferContractEventArgs>) => {
                     done();
                 };
                 const newProvider = web3Factory.getRpcProvider();
@@ -407,7 +407,7 @@ describe('TokenWrapper', () => {
         });
         it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (logEvent: LogEvent<TokenContractEventArgs>) => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: LogEvent<TokenContractEventArgs>) => {
                     done(new Error('Expected this subscription to have been cancelled'));
                 };
                 const subscriptionToken = zeroEx.token.subscribe(