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, 34 insertions, 0 deletions

diff --git a/packages/0x.js/src/contract_wrappers/generated/base_contract.ts b/packages/0x.js/src/contract_wrappers/generated/base_contract.ts
new file mode 100644
index 000000000..396a4d593
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/generated/base_contract.ts
@@ -0,0 +1,34 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+
+import {TxData, TxDataPayable} from '../../types';
+
+export class BaseContract {
+    protected web3ContractInstance: Web3.ContractInstance;
+    protected defaults: Partial<TxData>;
+    protected async applyDefaultsToTxDataAsync<T extends TxData|TxDataPayable>(
+        txData: T,
+        estimateGasAsync?: (txData: T) => Promise<number>,
+    ): Promise<TxData> {
+        // Gas amount sourced with the following priorities:
+        // 1. Optional param passed in to public method call
+        // 2. Global config passed in at library instantiation
+        // 3. Gas estimate calculation + safety margin
+        const removeUndefinedProperties = _.pickBy;
+        const txDataWithDefaults = {
+            ...removeUndefinedProperties(this.defaults),
+            ...removeUndefinedProperties(txData as any),
+            // HACK: TS can't prove that T is spreadable.
+            // Awaiting https://github.com/Microsoft/TypeScript/pull/13288 to be merged
+        };
+        if (_.isUndefined(txDataWithDefaults.gas) && !_.isUndefined(estimateGasAsync)) {
+            const estimatedGas = await estimateGasAsync(txData);
+            txDataWithDefaults.gas = estimatedGas;
+        }
+        return txDataWithDefaults;
+    }
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<TxData>) {
+        this.web3ContractInstance = web3ContractInstance;
+        this.defaults = defaults;
+    }
+}