2 files changed, 35 insertions, 19 deletions
diff --git a/packages/base-contract/src/index.ts b/packages/base-contract/src/index.ts
index 961da8842..c8cbd7886 100644
--- a/packages/base-contract/src/index.ts
+++ b/packages/base-contract/src/index.ts
@@ -1,40 +1,31 @@
 import { ContractAbi, DataItem, TxData, TxDataPayable } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as ethersContracts from 'ethers-contracts';
 import * as _ from 'lodash';
 
+import { formatABIDataItem } from './utils';
+
 export class BaseContract {
     protected _ethersInterface: ethersContracts.Interface;
     protected _web3Wrapper: Web3Wrapper;
     public abi: ContractAbi;
     public address: string;
-    protected static _transformABIData(
+    protected static _formatABIDataItemList(
         abis: DataItem[],
         values: any[],
-        transformation: (type: string, value: any) => any,
+        formatter: (type: string, value: any) => any,
     ): any {
-        return _.map(values, (value: any, i: number) =>
-            BaseContract._transformTypedData(abis[i].type, value, transformation),
-        );
+        return _.map(values, (value: any, i: number) => formatABIDataItem(abis[i], value, formatter));
     }
     protected static _lowercaseAddress(type: string, value: string): string {
         return type === 'address' ? value.toLowerCase() : value;
     }
-    protected static _bigNumberToString(type: string, value: string): string {
-        return _.isObject(value) && (value as any).isBigNumber ? value.toString() : value;
+    protected static _bigNumberToString(type: string, value: any): any {
+        return _.isObject(value) && value.isBigNumber ? value.toString() : value;
     }
-    private static _transformTypedData(
-        type: string,
-        values: any,
-        transformation: (type: string, value: any) => any,
-    ): any {
-        const trailingArrayRegex = /\[\d*\]$/;
-        if (type.match(trailingArrayRegex)) {
-            const arrayItemType = type.replace(trailingArrayRegex, '');
-            return _.map(values, value => this._transformTypedData(arrayItemType, value, transformation));
-        } else {
-            return transformation(type, values);
-        }
+    protected static _bnToBigNumber(type: string, value: any): any {
+        return _.isObject(value) && value._bn ? new BigNumber(value.toString()) : value;
     }
     protected async _applyDefaultsToTxDataAsync<T extends Partial<TxData | TxDataPayable>>(
         txData: T,
diff --git a/packages/base-contract/src/utils.ts b/packages/base-contract/src/utils.ts
new file mode 100644
index 000000000..4b86bb1ad
--- /dev/null
+++ b/packages/base-contract/src/utils.ts
@@ -0,0 +1,25 @@
+import { DataItem } from '@0xproject/types';
+import * as _ from 'lodash';
+
+// tslint:disable-next-line:completed-docs
+export function formatABIDataItem(abi: DataItem, value: any, formatter: (type: string, value: any) => any): any {
+    const trailingArrayRegex = /\[\d*\]$/;
+    if (abi.type.match(trailingArrayRegex)) {
+        const arrayItemType = abi.type.replace(trailingArrayRegex, '');
+        return _.map(value, val => {
+            const arrayItemAbi = {
+                ...abi,
+                type: arrayItemType,
+            };
+            return formatABIDataItem(arrayItemAbi, val, formatter);
+        });
+    } else if (abi.type === 'tuple') {
+        const formattedTuple: { [componentName: string]: DataItem } = {};
+        _.forEach(abi.components, componentABI => {
+            formattedTuple[componentABI.name] = formatABIDataItem(componentABI, value[componentABI.name], formatter);
+        });
+        return formattedTuple;
+    } else {
+        return formatter(abi.type, value);
+    }
+}