Return SignedOrder from signing utils.

Create a helper back in EIP712Utils for code cleanup.
Moved constants in order-utils into the constants object

packages/order-utils/src/eip712_utils.ts

@@ -0,0 +1,75 @@
+import { EIP712Object, EIP712TypedData, EIP712Types, Order, ZeroExTransaction } from '@0xproject/types';
+import * as _ from 'lodash';
+
+import { constants } from './constants';
+
+export const eip712Utils = {
+    /**
+     * Creates a EIP712TypedData object specific to the 0x protocol for use with signTypedData.
+     * @param   primaryType The primary type found in message
+     * @param   types The additional types for the data in message
+     * @param   message The contents of the message
+     * @param   exchangeAddress The address of the exchange contract
+     * @return  A typed data object
+     */
+    createTypedData: (
+        primaryType: string,
+        types: EIP712Types,
+        message: EIP712Object,
+        exchangeAddress: string,
+    ): EIP712TypedData => {
+        const typedData = {
+            types: {
+                EIP712Domain: constants.EIP712_DOMAIN_SCHEMA.parameters,
+                ...types,
+            },
+            domain: {
+                name: constants.EIP712_DOMAIN_NAME,
+                version: constants.EIP712_DOMAIN_VERSION,
+                verifyingContract: exchangeAddress,
+            },
+            message,
+            primaryType,
+        };
+        return typedData;
+    },
+    /**
+     * Creates an Order EIP712TypedData object for use with signTypedData.
+     * @param   Order the order
+     * @return  A typed data object
+     */
+    createOrderTypedData: (order: Order): EIP712TypedData => {
+        const normalizedOrder = _.mapValues(order, value => {
+            return !_.isString(value) ? value.toString() : value;
+        });
+        const typedData = eip712Utils.createTypedData(
+            constants.EIP712_ORDER_SCHEMA.name,
+            { Order: constants.EIP712_ORDER_SCHEMA.parameters },
+            normalizedOrder,
+            order.exchangeAddress,
+        );
+        return typedData;
+    },
+    /**
+     * Creates an ExecuteTransaction EIP712TypedData object for use with signTypedData and
+     * 0x Exchange executeTransaction.
+     * @param   ZeroExTransaction the 0x transaction
+     * @param   exchangeAddress The address of the exchange contract
+     * @return  A typed data object
+     */
+    createZeroExTransactionTypedData: (
+        zeroExTransaction: ZeroExTransaction,
+        exchangeAddress: string,
+    ): EIP712TypedData => {
+        const normalizedTransaction = _.mapValues(zeroExTransaction, value => {
+            return !_.isString(value) ? value.toString() : value;
+        });
+        const typedData = eip712Utils.createTypedData(
+            constants.EIP712_ZEROEX_TRANSACTION_SCHEMA.name,
+            { ZeroExTransaction: constants.EIP712_ZEROEX_TRANSACTION_SCHEMA.parameters },
+            normalizedTransaction,
+            exchangeAddress,
+        );
+        return typedData;
+    },
+};