Merge branch 'development' into feature/addSubproviders

* development: (50 commits)
  Add PR number to changelog
  Address feedback
  Add requestId to subscription messages and update json-schemas
  Remove isomorphic-fetch types from contracts package
  Update README
  Regenerate files
  Make it private
  Change package name
  Update README
  Make fileExtension configurable
  Rename abi-gen to typed-contracts
  Add docs for typed-contracts
  Remove TODOs
  Introduce separate ContextData type and rework it
  Check ABI is defined
  Introduce a const for 'contract.mustache'
  Improve error message
  Reuse util
  Fix a typo
  Introduce a const for 'function'
  ...

# Conflicts:
#	yarn.lock

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..fce15db6d
--- /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;
+    }
+}