1 files changed, 30 insertions, 0 deletions
diff --git a/packages/contracts/util/balances.ts b/packages/contracts/util/balances.ts
new file mode 100644
index 000000000..ef4abd7bf
--- /dev/null
+++ b/packages/contracts/util/balances.ts
@@ -0,0 +1,30 @@
+import {BigNumber} from 'bignumber.js';
+import * as _ from 'lodash';
+
+import {bigNumberConfigs} from './bignumber_config';
+import {BalancesByOwner, ContractInstance} from './types';
+
+bigNumberConfigs.configure();
+
+export class Balances {
+  private tokenContractInstances: ContractInstance[];
+  private ownerAddresses: string[];
+  constructor(tokenContractInstances: ContractInstance[], ownerAddresses: string[]) {
+    this.tokenContractInstances = tokenContractInstances;
+    this.ownerAddresses = ownerAddresses;
+  }
+  public async getAsync(): Promise<BalancesByOwner> {
+    const balancesByOwner: BalancesByOwner = {};
+    for (const tokenContractInstance of this.tokenContractInstances) {
+      for (const ownerAddress of this.ownerAddresses) {
+        let balance = await tokenContractInstance.balanceOf(ownerAddress);
+        balance = new BigNumber(balance);
+        if (_.isUndefined(balancesByOwner[ownerAddress])) {
+          balancesByOwner[ownerAddress] = {};
+        }
+        balancesByOwner[ownerAddress][tokenContractInstance.address] = balance;
+      }
+    }
+    return balancesByOwner;
+  }
+}