@0x/migrations: Update EP migration

packages/migrations/CHANGELOG.json

@@ -9,6 +9,10 @@
             {
                 "note": "Refactor `migration.ts` a little",
                 "pr": 2656
+            },
+            {
+                "note": "Update EP migration.",
+                "pr": "TODO"
             }
         ]
     },

packages/migrations/src/migration.ts

@@ -31,11 +31,9 @@ import {
     artifacts as exchangeProxyArtifacts,
     FillQuoteTransformerContract,
     fullMigrateAsync as fullMigrateExchangeProxyAsync,
-    ITokenSpenderContract,
-    ITransformERC20Contract,
+    IZeroExContract,
     PayTakerTransformerContract,
     WethTransformerContract,
-    ZeroExContract,
 } from '@0x/contracts-zero-ex';
 import { Web3ProviderEngine, ZeroExProvider } from '@0x/subproviders';
 import { BigNumber, providerUtils } from '@0x/utils';
@@ -400,7 +398,7 @@ async function _migrateExchangeProxyAsync(
     txDefaults: TxData,
 ): Promise<
     [
-        ZeroExContract,
+        IZeroExContract,
         FillQuoteTransformerContract,
         PayTakerTransformerContract,
         WethTransformerContract,
@@ -410,16 +408,8 @@ async function _migrateExchangeProxyAsync(
     ]
 > {
     const exchangeProxy = await fullMigrateExchangeProxyAsync(txDefaults.from, provider, txDefaults);
-    const exchangeProxyAllowanceTargetAddress = await new ITokenSpenderContract(
-        exchangeProxy.address,
-        provider,
-        txDefaults,
-    )
-        .getAllowanceTarget()
-        .callAsync();
-    const exchangeProxyFlashWalletAddress = await new ITransformERC20Contract(exchangeProxy.address, provider)
-        .getTransformWallet()
-        .callAsync();
+    const exchangeProxyAllowanceTargetAddress = await exchangeProxy.getAllowanceTarget().callAsync();
+    const exchangeProxyFlashWalletAddress = await exchangeProxy.getTransformWallet().callAsync();
 
     // Deploy transformers.
     const fillQuoteTransformer = await FillQuoteTransformerContract.deployFrom0xArtifactAsync(