3 files changed, 17 insertions, 8 deletions
diff --git a/packages/0x.js/CHANGELOG.json b/packages/0x.js/CHANGELOG.json
index 913b7a76e..0a10e1ccf 100644
--- a/packages/0x.js/CHANGELOG.json
+++ b/packages/0x.js/CHANGELOG.json
@@ -21,6 +21,9 @@
         "changes": [
             {
                 "note": "Dependencies updated"
+            },
+            {
+                "note": "Update ecSignOrderHashAsync to return the signature as a string for immediate use in contracts"
             }
         ],
         "timestamp": 1532605697
diff --git a/packages/0x.js/src/0x.ts b/packages/0x.js/src/0x.ts
index 2a2b82f63..86859c368 100644
--- a/packages/0x.js/src/0x.ts
+++ b/packages/0x.js/src/0x.ts
@@ -14,13 +14,19 @@ import {
     ecSignOrderHashAsync,
     generatePseudoRandomSalt,
     isValidSignatureAsync,
-    MessagePrefixOpts,
     orderHashUtils,
 } from '@0xproject/order-utils';
 // HACK: Since we export assetDataUtils from ZeroEx and it has AssetProxyId, ERC20AssetData and ERC721AssetData
 // in it's public interface, we need to import these types here.
 // tslint:disable-next-line:no-unused-variable
-import { AssetProxyId, ECSignature, ERC20AssetData, ERC721AssetData, Order, SignedOrder } from '@0xproject/types';
+import {
+    AssetProxyId,
+    ERC20AssetData,
+    ERC721AssetData,
+    Order,
+    SignedOrder,
+    SignerProviderType,
+} from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
@@ -238,19 +244,19 @@ export class ZeroEx {
      * @param   orderHash       Hex encoded orderHash to sign.
      * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
      *          must be available via the Provider supplied to 0x.js.
-     * @param   MessagePrefixOpts  Options regarding the desired prefix and whether to add it before calling `eth_sign`
-     * @return  An object containing the Elliptic curve signature parameters generated by signing the orderHash.
+     * @param   SignerProviderType  The type of Signer Provider which implements `eth_sign`. E.g Metamask, Ledger, Trezor or EthSign.
+     * @return  A hex encoded string of the Elliptic curve signature parameters generated by signing the orderHash and signature type.
      */
     public async ecSignOrderHashAsync(
         orderHash: string,
         signerAddress: string,
-        messagePrefixOpts: MessagePrefixOpts,
-    ): Promise<ECSignature> {
+        signerProviderType: SignerProviderType,
+    ): Promise<string> {
         const signature = await ecSignOrderHashAsync(
             this._contractWrappers.getProvider(),
             orderHash,
             signerAddress,
-            messagePrefixOpts,
+            signerProviderType,
         );
         return signature;
     }
diff --git a/packages/0x.js/src/index.ts b/packages/0x.js/src/index.ts
index 95ca07eea..1e5c0c270 100644
--- a/packages/0x.js/src/index.ts
+++ b/packages/0x.js/src/index.ts
@@ -1,12 +1,12 @@
 export { ZeroEx } from './0x';
 
-export { MessagePrefixType, MessagePrefixOpts } from '@0xproject/order-utils';
 export { Web3ProviderEngine, RPCSubprovider } from '@0xproject/subproviders';
 
 export {
     ExchangeContractErrs,
     Order,
     SignedOrder,
+    SignerProviderType,
     ECSignature,
     OrderStateValid,
     OrderStateInvalid,