Fix callback types

9 files changed, 203 insertions, 157 deletions

diff --git a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
index d308d207e..9c4e5dfd3 100644
--- a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
@@ -87,7 +87,7 @@ export class ContractWrapper {
         }
         const filterToken = filterUtils.generateUUID();
         this._filters[filterToken] = filter;
-        this._filterCallbacks[filterToken] = callback;
+        this._filterCallbacks[filterToken] = callback as EventCallback<ContractEventArgs>;
         return filterToken;
     }
     protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
diff --git a/packages/0x.js/test/ether_token_wrapper_test.ts b/packages/0x.js/test/ether_token_wrapper_test.ts
index db7acc8e5..b810fc9f1 100644
--- a/packages/0x.js/test/ether_token_wrapper_test.ts
+++ b/packages/0x.js/test/ether_token_wrapper_test.ts
@@ -22,6 +22,7 @@ import { DoneCallback } from '../src/types';
 
 import { chaiSetup } from './utils/chai_setup';
 import { constants } from './utils/constants';
+import { reportNodeCallbackErrors } from './utils/report_callback_errors';
 import { TokenUtils } from './utils/token_utils';
 import { web3Factory } from './utils/web3_factory';
 
@@ -153,19 +154,19 @@ describe('EtherTokenWrapper', () => {
         // Source: https://github.com/mochajs/mocha/issues/2407
         it('Should receive the Transfer event when tokens are transfered', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
-                    expect(err).to.be.null();
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    expect(logEvent.log.logIndex).to.be.equal(0);
-                    expect(logEvent.log.transactionIndex).to.be.equal(0);
-                    expect(logEvent.log.blockNumber).to.be.a('number');
-                    const args = logEvent.log.args;
-                    expect(args._from).to.be.equal(addressWithETH);
-                    expect(args._to).to.be.equal(addressWithoutFunds);
-                    expect(args._value).to.be.bignumber.equal(transferAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
+                        expect(logEvent).to.not.be.undefined();
+                        expect(logEvent.isRemoved).to.be.false();
+                        expect(logEvent.log.logIndex).to.be.equal(0);
+                        expect(logEvent.log.transactionIndex).to.be.equal(0);
+                        expect(logEvent.log.blockNumber).to.be.a('number');
+                        const args = logEvent.log.args;
+                        expect(args._from).to.be.equal(addressWithETH);
+                        expect(args._to).to.be.equal(addressWithoutFunds);
+                        expect(args._value).to.be.bignumber.equal(transferAmount);
+                    },
+                );
                 await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
                 zeroEx.etherToken.subscribe(etherTokenAddress, EtherTokenEvents.Transfer, indexFilterValues, callback);
                 await zeroEx.token.transferAsync(
@@ -178,16 +179,16 @@ describe('EtherTokenWrapper', () => {
         });
         it('Should receive the Approval event when allowance is being set', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    expect(err).to.be.null();
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    const args = logEvent.log.args;
-                    expect(args._owner).to.be.equal(addressWithETH);
-                    expect(args._spender).to.be.equal(addressWithoutFunds);
-                    expect(args._value).to.be.bignumber.equal(allowanceAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        expect(logEvent).to.not.be.undefined();
+                        expect(logEvent.isRemoved).to.be.false();
+                        const args = logEvent.log.args;
+                        expect(args._owner).to.be.equal(addressWithETH);
+                        expect(args._spender).to.be.equal(addressWithoutFunds);
+                        expect(args._value).to.be.bignumber.equal(allowanceAmount);
+                    },
+                );
                 zeroEx.etherToken.subscribe(etherTokenAddress, EtherTokenEvents.Approval, indexFilterValues, callback);
                 await zeroEx.token.setAllowanceAsync(
                     etherTokenAddress,
@@ -199,30 +200,30 @@ describe('EtherTokenWrapper', () => {
         });
         it('Should receive the Deposit event when ether is being deposited', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<DepositContractEventArgs>) => {
-                    expect(err).to.be.null();
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    const args = logEvent.log.args;
-                    expect(args._owner).to.be.equal(addressWithETH);
-                    expect(args._value).to.be.bignumber.equal(depositAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<DepositContractEventArgs>) => {
+                        expect(logEvent).to.not.be.undefined();
+                        expect(logEvent.isRemoved).to.be.false();
+                        const args = logEvent.log.args;
+                        expect(args._owner).to.be.equal(addressWithETH);
+                        expect(args._value).to.be.bignumber.equal(depositAmount);
+                    },
+                );
                 zeroEx.etherToken.subscribe(etherTokenAddress, EtherTokenEvents.Deposit, indexFilterValues, callback);
                 await zeroEx.etherToken.depositAsync(etherTokenAddress, depositAmount, addressWithETH);
             })().catch(done);
         });
         it('Should receive the Withdrawal event when ether is being withdrawn', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<WithdrawalContractEventArgs>) => {
-                    expect(err).to.be.null();
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    const args = logEvent.log.args;
-                    expect(args._owner).to.be.equal(addressWithETH);
-                    expect(args._value).to.be.bignumber.equal(depositAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<WithdrawalContractEventArgs>) => {
+                        expect(logEvent).to.not.be.undefined();
+                        expect(logEvent.isRemoved).to.be.false();
+                        const args = logEvent.log.args;
+                        expect(args._owner).to.be.equal(addressWithETH);
+                        expect(args._value).to.be.bignumber.equal(depositAmount);
+                    },
+                );
                 await zeroEx.etherToken.depositAsync(etherTokenAddress, depositAmount, addressWithETH);
                 zeroEx.etherToken.subscribe(
                     etherTokenAddress,
@@ -235,18 +236,18 @@ describe('EtherTokenWrapper', () => {
         });
         it('should cancel outstanding subscriptions when ZeroEx.setProvider is called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 zeroEx.etherToken.subscribe(
                     etherTokenAddress,
                     EtherTokenEvents.Transfer,
                     indexFilterValues,
                     callbackNeverToBeCalled,
                 );
-                const callbackToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done();
-                };
+                const callbackToBeCalled = reportNodeCallbackErrors(done)();
                 const newProvider = web3Factory.getRpcProvider();
                 zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);
                 await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
@@ -266,9 +267,11 @@ describe('EtherTokenWrapper', () => {
         });
         it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
                 const subscriptionToken = zeroEx.etherToken.subscribe(
                     etherTokenAddress,
diff --git a/packages/0x.js/test/exchange_wrapper_test.ts b/packages/0x.js/test/exchange_wrapper_test.ts
index cb927ba8f..c501ce998 100644
--- a/packages/0x.js/test/exchange_wrapper_test.ts
+++ b/packages/0x.js/test/exchange_wrapper_test.ts
@@ -1,6 +1,7 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
+import * as _ from 'lodash';
 import 'mocha';
 import * as Web3 from 'web3';
 
@@ -22,6 +23,7 @@ import { BlockParamLiteral, DoneCallback } from '../src/types';
 import { chaiSetup } from './utils/chai_setup';
 import { constants } from './utils/constants';
 import { FillScenarios } from './utils/fill_scenarios';
+import { reportNodeCallbackErrors } from './utils/report_callback_errors';
 import { TokenUtils } from './utils/token_utils';
 import { web3Factory } from './utils/web3_factory';
 
@@ -31,6 +33,13 @@ const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);
 
 const NON_EXISTENT_ORDER_HASH = '0x79370342234e7acd6bbeac335bd3bb1d368383294b64b8160a00f4060e4d3777';
 
+function noError<T>(err: Error | null, value: T | undefined): value is T {
+    if (_.isNull(err)) {
+        throw err;
+    }
+    return _.isNull(err);
+}
+
 describe('ExchangeWrapper', () => {
     let web3: Web3;
     let zeroEx: ZeroEx;
@@ -851,10 +860,11 @@ 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 = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                        expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
+                    },
+                );
                 zeroEx.exchange.subscribe(ExchangeEvents.LogFill, indexFilterValues, callback);
                 await zeroEx.exchange.fillOrderAsync(
                     signedOrder,
@@ -866,28 +876,32 @@ describe('ExchangeWrapper', () => {
         });
         it('Should receive the LogCancel event when an order is cancelled', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<LogCancelContractEventArgs>) => {
-                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogCancel);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<LogCancelContractEventArgs>) => {
+                        expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogCancel);
+                    },
+                );
                 zeroEx.exchange.subscribe(ExchangeEvents.LogCancel, indexFilterValues, callback);
                 await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelTakerAmountInBaseUnits);
             })().catch(done);
         });
         it('Outstanding subscriptions are cancelled when zeroEx.setProvider called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 zeroEx.exchange.subscribe(ExchangeEvents.LogFill, indexFilterValues, callbackNeverToBeCalled);
 
                 const newProvider = web3Factory.getRpcProvider();
                 zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);
 
-                const callback = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                        expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
+                    },
+                );
                 zeroEx.exchange.subscribe(ExchangeEvents.LogFill, indexFilterValues, callback);
                 await zeroEx.exchange.fillOrderAsync(
                     signedOrder,
@@ -899,9 +913,11 @@ describe('ExchangeWrapper', () => {
         });
         it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 const subscriptionToken = zeroEx.exchange.subscribe(
                     ExchangeEvents.LogFill,
                     indexFilterValues,
diff --git a/packages/0x.js/test/expiration_watcher_test.ts b/packages/0x.js/test/expiration_watcher_test.ts
index e7ba3533a..770615f88 100644
--- a/packages/0x.js/test/expiration_watcher_test.ts
+++ b/packages/0x.js/test/expiration_watcher_test.ts
@@ -15,7 +15,7 @@ import { utils } from '../src/utils/utils';
 import { chaiSetup } from './utils/chai_setup';
 import { constants as testConstants } from './utils/constants';
 import { FillScenarios } from './utils/fill_scenarios';
-import { reportCallbackErrors } from './utils/report_callback_errors';
+import { reportNoErrorCallbackErrors } from './utils/report_callback_errors';
 import { TokenUtils } from './utils/token_utils';
 import { web3Factory } from './utils/web3_factory';
 
@@ -87,10 +87,9 @@ describe('ExpirationWatcher', () => {
             );
             const orderHash = ZeroEx.getOrderHashHex(signedOrder);
             expirationWatcher.addOrder(orderHash, signedOrder.expirationUnixTimestampSec.times(1000));
-            const callbackAsync = reportCallbackErrors(done)(async (hash: string) => {
+            const callbackAsync = reportNoErrorCallbackErrors(done)((hash: string) => {
                 expect(hash).to.be.equal(orderHash);
                 expect(utils.getCurrentUnixTimestampSec()).to.be.bignumber.gte(expirationUnixTimestampSec);
-                done();
             });
             expirationWatcher.subscribe(callbackAsync);
             timer.tick(orderLifetimeSec * 1000);
@@ -110,7 +109,7 @@ describe('ExpirationWatcher', () => {
             );
             const orderHash = ZeroEx.getOrderHashHex(signedOrder);
             expirationWatcher.addOrder(orderHash, signedOrder.expirationUnixTimestampSec.times(1000));
-            const callbackAsync = reportCallbackErrors(done)(async (hash: string) => {
+            const callbackAsync = reportNoErrorCallbackErrors(done)(async (hash: string) => {
                 done(new Error('Emitted expiration went before the order actually expired'));
             });
             expirationWatcher.subscribe(callbackAsync);
@@ -146,7 +145,8 @@ describe('ExpirationWatcher', () => {
             expirationWatcher.addOrder(orderHash2, signedOrder2.expirationUnixTimestampSec.times(1000));
             expirationWatcher.addOrder(orderHash1, signedOrder1.expirationUnixTimestampSec.times(1000));
             const expirationOrder = [orderHash1, orderHash2];
-            const callbackAsync = reportCallbackErrors(done)(async (hash: string) => {
+            const expectToBeCalledOnce = false;
+            const callbackAsync = reportNoErrorCallbackErrors(done, expectToBeCalledOnce)((hash: string) => {
                 const orderHash = expirationOrder.shift();
                 expect(hash).to.be.equal(orderHash);
                 if (_.isEmpty(expirationOrder)) {
diff --git a/packages/0x.js/test/order_state_watcher_test.ts b/packages/0x.js/test/order_state_watcher_test.ts
index 9f284cfd9..311752bd8 100644
--- a/packages/0x.js/test/order_state_watcher_test.ts
+++ b/packages/0x.js/test/order_state_watcher_test.ts
@@ -20,7 +20,7 @@ import { DoneCallback } from '../src/types';
 import { chaiSetup } from './utils/chai_setup';
 import { constants } from './utils/constants';
 import { FillScenarios } from './utils/fill_scenarios';
-import { reportCallbackErrors } from './utils/report_callback_errors';
+import { reportNoErrorCallbackErrors } from './utils/report_callback_errors';
 import { TokenUtils } from './utils/token_utils';
 import { web3Factory } from './utils/web3_factory';
 
@@ -134,12 +134,11 @@ describe('OrderStateWatcher', () => {
                 );
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.false();
                     const invalidOrderState = orderState as OrderStateInvalid;
                     expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                     expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.InsufficientMakerAllowance);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
                 await zeroEx.token.setProxyAllowanceAsync(makerToken.address, maker, new BigNumber(0));
@@ -155,7 +154,7 @@ describe('OrderStateWatcher', () => {
                     fillableAmount,
                 );
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     throw new Error('OrderState callback fired for irrelevant order');
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
@@ -179,12 +178,11 @@ describe('OrderStateWatcher', () => {
                 );
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.false();
                     const invalidOrderState = orderState as OrderStateInvalid;
                     expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                     expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.InsufficientMakerBalance);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
                 const anyRecipient = taker;
@@ -204,12 +202,11 @@ describe('OrderStateWatcher', () => {
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.false();
                     const invalidOrderState = orderState as OrderStateInvalid;
                     expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                     expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderRemainingFillAmountZero);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
 
@@ -237,7 +234,7 @@ describe('OrderStateWatcher', () => {
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.true();
                     const validOrderState = orderState as OrderStateValid;
                     expect(validOrderState.orderHash).to.be.equal(orderHash);
@@ -251,7 +248,6 @@ describe('OrderStateWatcher', () => {
                         remainingFillable,
                     );
                     expect(orderRelevantState.makerBalance).to.be.bignumber.equal(remainingMakerBalance);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
                 const shouldThrowOnInsufficientBalanceOrAllowance = true;
@@ -277,9 +273,7 @@ describe('OrderStateWatcher', () => {
                     fillableAmount,
                     taker,
                 );
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
-                    done();
-                });
+                const callback = reportNoErrorCallbackErrors(done)();
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
                 zeroEx.orderStateWatcher.subscribe(callback);
                 await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, maker, new BigNumber(0));
@@ -301,7 +295,7 @@ describe('OrderStateWatcher', () => {
                     const fillAmountInBaseUnits = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
                     const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         expect(orderState.isValid).to.be.true();
                         const validOrderState = orderState as OrderStateValid;
                         expect(validOrderState.orderHash).to.be.equal(orderHash);
@@ -312,7 +306,6 @@ describe('OrderStateWatcher', () => {
                         expect(orderRelevantState.remainingFillableTakerTokenAmount).to.be.bignumber.equal(
                             ZeroEx.toBaseUnitAmount(new BigNumber(8), decimals),
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     const shouldThrowOnInsufficientBalanceOrAllowance = true;
@@ -337,7 +330,7 @@ describe('OrderStateWatcher', () => {
                     const changedMakerApprovalAmount = ZeroEx.toBaseUnitAmount(new BigNumber(3), decimals);
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         const validOrderState = orderState as OrderStateValid;
                         const orderRelevantState = validOrderState.orderRelevantState;
                         expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
@@ -346,7 +339,6 @@ describe('OrderStateWatcher', () => {
                         expect(orderRelevantState.remainingFillableTakerTokenAmount).to.be.bignumber.equal(
                             changedMakerApprovalAmount,
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     await zeroEx.token.setProxyAllowanceAsync(makerToken.address, maker, changedMakerApprovalAmount);
@@ -368,7 +360,7 @@ describe('OrderStateWatcher', () => {
                     const transferAmount = makerBalance.sub(remainingAmount);
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         expect(orderState.isValid).to.be.true();
                         const validOrderState = orderState as OrderStateValid;
                         const orderRelevantState = validOrderState.orderRelevantState;
@@ -378,7 +370,6 @@ describe('OrderStateWatcher', () => {
                         expect(orderRelevantState.remainingFillableTakerTokenAmount).to.be.bignumber.equal(
                             remainingAmount,
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     await zeroEx.token.transferAsync(makerToken.address, maker, ZeroEx.NULL_ADDRESS, transferAmount);
@@ -404,14 +395,13 @@ describe('OrderStateWatcher', () => {
                     const transferTokenAmount = makerFee.sub(remainingTokenAmount);
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         expect(orderState.isValid).to.be.true();
                         const validOrderState = orderState as OrderStateValid;
                         const orderRelevantState = validOrderState.orderRelevantState;
                         expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
                             remainingTokenAmount,
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     await zeroEx.exchange.cancelOrderAsync(signedOrder, transferTokenAmount);
@@ -439,13 +429,12 @@ describe('OrderStateWatcher', () => {
                     const transferTokenAmount = makerFee.sub(remainingTokenAmount);
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         const validOrderState = orderState as OrderStateValid;
                         const orderRelevantState = validOrderState.orderRelevantState;
                         expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
                             remainingFeeAmount,
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, maker, remainingFeeAmount);
@@ -475,13 +464,12 @@ describe('OrderStateWatcher', () => {
 
                     zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                         const validOrderState = orderState as OrderStateValid;
                         const orderRelevantState = validOrderState.orderRelevantState;
                         expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
                             fillableAmount,
                         );
-                        done();
                     });
                     zeroEx.orderStateWatcher.subscribe(callback);
                     await zeroEx.token.setProxyAllowanceAsync(
@@ -504,12 +492,11 @@ describe('OrderStateWatcher', () => {
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.false();
                     const invalidOrderState = orderState as OrderStateInvalid;
                     expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                     expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderRemainingFillAmountZero);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
 
@@ -529,12 +516,11 @@ describe('OrderStateWatcher', () => {
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.false();
                     const invalidOrderState = orderState as OrderStateInvalid;
                     expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                     expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderFillRoundingError);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
                 await zeroEx.exchange.cancelOrderAsync(
@@ -557,13 +543,12 @@ describe('OrderStateWatcher', () => {
                 const orderHash = ZeroEx.getOrderHashHex(signedOrder);
                 zeroEx.orderStateWatcher.addOrder(signedOrder);
 
-                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                const callback = reportNoErrorCallbackErrors(done)((orderState: OrderState) => {
                     expect(orderState.isValid).to.be.true();
                     const validOrderState = orderState as OrderStateValid;
                     expect(validOrderState.orderHash).to.be.equal(orderHash);
                     const orderRelevantState = validOrderState.orderRelevantState;
                     expect(orderRelevantState.cancelledTakerTokenAmount).to.be.bignumber.equal(cancelAmountInBaseUnits);
-                    done();
                 });
                 zeroEx.orderStateWatcher.subscribe(callback);
                 await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelAmountInBaseUnits);
diff --git a/packages/0x.js/test/subscription_test.ts b/packages/0x.js/test/subscription_test.ts
index d6269f15f..f44bfecf6 100644
--- a/packages/0x.js/test/subscription_test.ts
+++ b/packages/0x.js/test/subscription_test.ts
@@ -11,7 +11,7 @@ import { DoneCallback } from '../src/types';
 
 import { chaiSetup } from './utils/chai_setup';
 import { constants } from './utils/constants';
-import { reportCallbackErrors } from './utils/report_callback_errors';
+import { assertNodeCallbackError } from './utils/report_callback_errors';
 import { web3Factory } from './utils/web3_factory';
 
 chaiSetup.configure();
@@ -59,13 +59,7 @@ describe('SubscriptionTest', () => {
         it('Should receive the Error when an error occurs while fetching the block', (done: DoneCallback) => {
             (async () => {
                 const errMsg = 'Error fetching block';
-                const callback = reportCallbackErrors(done)(
-                    (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                        expect(err.message).to.be.equal(errMsg);
-                        expect(logEvent).to.be.undefined();
-                        done();
-                    },
-                );
+                const callback = assertNodeCallbackError(done, errMsg);
                 stubs = [Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync').throws(new Error(errMsg))];
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                 await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
@@ -74,13 +68,7 @@ describe('SubscriptionTest', () => {
         it('Should receive the Error when an error occurs while reconciling the new block', (done: DoneCallback) => {
             (async () => {
                 const errMsg = 'Error fetching logs';
-                const callback = reportCallbackErrors(done)(
-                    (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                        expect(err.message).to.be.equal(errMsg);
-                        expect(logEvent).to.be.undefined();
-                        done();
-                    },
-                );
+                const callback = assertNodeCallbackError(done, errMsg);
                 stubs = [Sinon.stub((zeroEx as any)._web3Wrapper, 'getLogsAsync').throws(new Error(errMsg))];
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                 await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
@@ -88,7 +76,7 @@ describe('SubscriptionTest', () => {
         });
         it('Should allow unsubscribeAll to be called successfully after an error', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => _.noop;
+                const callback = (err: Error | null, logEvent?: DecodedLogEvent<ApprovalContractEventArgs>) => _.noop;
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                 stubs = [Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync').throws(new Error('JSON RPC error'))];
                 zeroEx.token.unsubscribeAll();
diff --git a/packages/0x.js/test/token_wrapper_test.ts b/packages/0x.js/test/token_wrapper_test.ts
index 296a704dd..4ba1f07c5 100644
--- a/packages/0x.js/test/token_wrapper_test.ts
+++ b/packages/0x.js/test/token_wrapper_test.ts
@@ -20,6 +20,7 @@ import { DoneCallback } from '../src/types';
 
 import { chaiSetup } from './utils/chai_setup';
 import { constants } from './utils/constants';
+import { reportNodeCallbackErrors } from './utils/report_callback_errors';
 import { TokenUtils } from './utils/token_utils';
 import { web3Factory } from './utils/web3_factory';
 
@@ -386,46 +387,47 @@ 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 = (err: Error, logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    expect(logEvent.log.logIndex).to.be.equal(0);
-                    expect(logEvent.log.transactionIndex).to.be.equal(0);
-                    expect(logEvent.log.blockNumber).to.be.a('number');
-                    const args = logEvent.log.args;
-                    expect(args._from).to.be.equal(coinbase);
-                    expect(args._to).to.be.equal(addressWithoutFunds);
-                    expect(args._value).to.be.bignumber.equal(transferAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
+                        expect(logEvent.isRemoved).to.be.false();
+                        expect(logEvent.log.logIndex).to.be.equal(0);
+                        expect(logEvent.log.transactionIndex).to.be.equal(0);
+                        expect(logEvent.log.blockNumber).to.be.a('number');
+                        const args = logEvent.log.args;
+                        expect(args._from).to.be.equal(coinbase);
+                        expect(args._to).to.be.equal(addressWithoutFunds);
+                        expect(args._value).to.be.bignumber.equal(transferAmount);
+                    },
+                );
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Transfer, indexFilterValues, callback);
                 await zeroEx.token.transferAsync(tokenAddress, coinbase, addressWithoutFunds, transferAmount);
             })().catch(done);
         });
         it('Should receive the Approval event when allowance is being set', (done: DoneCallback) => {
             (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.isRemoved).to.be.false();
-                    const args = logEvent.log.args;
-                    expect(args._owner).to.be.equal(coinbase);
-                    expect(args._spender).to.be.equal(addressWithoutFunds);
-                    expect(args._value).to.be.bignumber.equal(allowanceAmount);
-                    done();
-                };
+                const callback = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        expect(logEvent).to.not.be.undefined();
+                        expect(logEvent.isRemoved).to.be.false();
+                        const args = logEvent.log.args;
+                        expect(args._owner).to.be.equal(coinbase);
+                        expect(args._spender).to.be.equal(addressWithoutFunds);
+                        expect(args._value).to.be.bignumber.equal(allowanceAmount);
+                    },
+                );
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                 await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
             })().catch(done);
         });
         it('Outstanding subscriptions are cancelled when zeroEx.setProvider called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled);
-                const callbackToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done();
-                };
+                const callbackToBeCalled = reportNodeCallbackErrors(done)();
                 const newProvider = web3Factory.getRpcProvider();
                 zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);
                 zeroEx.token.subscribe(tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackToBeCalled);
@@ -434,9 +436,11 @@ describe('TokenWrapper', () => {
         });
         it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
             (async () => {
-                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    done(new Error('Expected this subscription to have been cancelled'));
-                };
+                const callbackNeverToBeCalled = reportNodeCallbackErrors(done)(
+                    (logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        done(new Error('Expected this subscription to have been cancelled'));
+                    },
+                );
                 const subscriptionToken = zeroEx.token.subscribe(
                     tokenAddress,
                     TokenEvents.Transfer,
diff --git a/packages/0x.js/test/utils/report_callback_errors.ts b/packages/0x.js/test/utils/report_callback_errors.ts
index 8a8f4d966..7890e7cd3 100644
--- a/packages/0x.js/test/utils/report_callback_errors.ts
+++ b/packages/0x.js/test/utils/report_callback_errors.ts
@@ -1,10 +1,22 @@
-import { DoneCallback } from '../../src/types';
+import * as chai from 'chai';
+import * as _ from 'lodash';
 
-export const reportCallbackErrors = (done: DoneCallback) => {
-    return (f: (...args: any[]) => void) => {
-        const wrapped = async (...args: any[]) => {
+import { DoneCallback, OrderState } from '../../src/types';
+
+const expect = chai.expect;
+
+export const reportNoErrorCallbackErrors = (done: DoneCallback, expectToBeCalledOnce = true) => {
+    return <T>(f?: (value: T) => void) => {
+        const wrapped = (value: T) => {
+            if (_.isUndefined(f)) {
+                done();
+                return;
+            }
             try {
-                f(...args);
+                f(value);
+                if (expectToBeCalledOnce) {
+                    done();
+                }
             } catch (err) {
                 done(err);
             }
@@ -12,3 +24,41 @@ export const reportCallbackErrors = (done: DoneCallback) => {
         return wrapped;
     };
 };
+
+export const reportNodeCallbackErrors = (done: DoneCallback) => {
+    return <T>(f?: (value: T) => void) => {
+        const wrapped = (error: Error | null, value: T | undefined) => {
+            if (!_.isNull(error)) {
+                done(error);
+            } else {
+                if (_.isUndefined(f)) {
+                    done();
+                    return;
+                }
+                try {
+                    f(value as T);
+                    done();
+                } catch (err) {
+                    done(err);
+                }
+            }
+        };
+        return wrapped;
+    };
+};
+
+export const assertNodeCallbackError = (done: DoneCallback, errMsg: string) => {
+    const wrapped = <T>(error: Error | null, value: T | undefined) => {
+        if (_.isNull(error)) {
+            done(new Error('Expected callback to receive an error'));
+        } else {
+            try {
+                expect(error.message).to.be.equal(errMsg);
+                done();
+            } catch (err) {
+                done(err);
+            }
+        }
+    };
+    return wrapped;
+};
diff --git a/packages/0x.js/tsconfig.json b/packages/0x.js/tsconfig.json
index 1defcc4a4..117f51e83 100644
--- a/packages/0x.js/tsconfig.json
+++ b/packages/0x.js/tsconfig.json
@@ -2,7 +2,7 @@
     "extends": "../../tsconfig",
     "compilerOptions": {
         "outDir": "lib",
-        "strict": false
+        "noImplicitThis": false
     },
     "include": [
         "./src/**/*",