Use new check for isBigNumber

2 files changed, 4 insertions, 7 deletions

diff --git a/packages/web3-wrapper/src/utils.ts b/packages/web3-wrapper/src/utils.ts
index 1b67518b1..1aba3c75a 100644
--- a/packages/web3-wrapper/src/utils.ts
+++ b/packages/web3-wrapper/src/utils.ts
@@ -2,10 +2,6 @@ import { BigNumber } from '@0x/utils';
 import * as _ from 'lodash';
 
 export const utils = {
-    isBigNumber(value: any): boolean {
-        const isBigNumber = _.isObject(value) && value.isBigNumber;
-        return isBigNumber;
-    },
     convertHexToNumber(value: string): number {
         const valueBigNumber = new BigNumber(value);
         const valueNumber = valueBigNumber.toNumber();
@@ -20,7 +16,7 @@ export const utils = {
     },
     convertAmountToBigNumber(value: string | number | BigNumber): BigNumber {
         const num = value || 0;
-        const isBigNumber = utils.isBigNumber(num);
+        const isBigNumber = BigNumber.isBigNumber(num);
         if (isBigNumber) {
             return num as BigNumber;
         }
diff --git a/packages/web3-wrapper/test/web3_wrapper_test.ts b/packages/web3-wrapper/test/web3_wrapper_test.ts
index 935c67636..e8732bcbe 100644
--- a/packages/web3-wrapper/test/web3_wrapper_test.ts
+++ b/packages/web3-wrapper/test/web3_wrapper_test.ts
@@ -1,3 +1,4 @@
+import { BigNumber } from '@0x/utils';
 import * as chai from 'chai';
 import { BlockParamLiteral, JSONRPCErrorCallback, JSONRPCRequestPayload, TransactionReceipt } from 'ethereum-types';
 import * as Ganache from 'ganache-core';
@@ -118,7 +119,7 @@ describe('Web3Wrapper tests', () => {
                 throw new Error('Expected block to exist');
             }
             expect(blockIfExists.number).to.be.equal(0);
-            expect(utils.isBigNumber(blockIfExists.difficulty)).to.equal(true);
+            expect(BigNumber.isBigNumber(blockIfExists.difficulty)).to.equal(true);
             expect(_.isNumber(blockIfExists.gasLimit)).to.equal(true);
         });
         it('gets block when supplied a block number', async () => {
@@ -151,7 +152,7 @@ describe('Web3Wrapper tests', () => {
             const blockParamLiteral = BlockParamLiteral.Earliest;
             const block = await web3Wrapper.getBlockWithTransactionDataAsync(blockParamLiteral);
             expect(block.number).to.be.equal(0);
-            expect(utils.isBigNumber(block.difficulty)).to.equal(true);
+            expect(BigNumber.isBigNumber(block.difficulty)).to.equal(true);
             expect(_.isNumber(block.gasLimit)).to.equal(true);
         });
         it('should throw if supplied invalid blockParam value', async () => {