From 3af174b5907ff0c5da6f2f43930d55c796531c1d Mon Sep 17 00:00:00 2001
From: Dan J Miller <danjm.com@gmail.com>
Date: Wed, 9 Jun 2021 22:18:05 -0230
Subject: [PATCH] Stringify gas estimate in backend, before it is serialized
 and sent to ui (#11266)

* Stringify gas estimate in backend, before it is serialized and sent to ui

* Fix send.utils.test.js
---
 app/scripts/metamask-controller.js | 2 +-
 ui/pages/send/send.utils.js        | 6 +-----
 ui/pages/send/send.utils.test.js   | 2 +-
 3 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 67b8286a7..ecee4dd0b 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -1937,7 +1937,7 @@ export default class MetamaskController extends EventEmitter {
             return reject(err);
           }
 
-          return resolve(res);
+          return resolve(res.toString(16));
         },
       );
     });
diff --git a/ui/pages/send/send.utils.js b/ui/pages/send/send.utils.js
index 1603061e2..889015a77 100644
--- a/ui/pages/send/send.utils.js
+++ b/ui/pages/send/send.utils.js
@@ -254,11 +254,7 @@ async function estimateGasForSend({
   // run tx
   try {
     const estimatedGas = await estimateGasMethod(paramsForGasEstimate);
-    const estimateWithBuffer = addGasBuffer(
-      estimatedGas.toString(16),
-      blockGasLimit,
-      1.5,
-    );
+    const estimateWithBuffer = addGasBuffer(estimatedGas, blockGasLimit, 1.5);
     return addHexPrefix(estimateWithBuffer);
   } catch (error) {
     const simulationFailed =
diff --git a/ui/pages/send/send.utils.test.js b/ui/pages/send/send.utils.test.js
index 06d3d8edc..91b94d8ef 100644
--- a/ui/pages/send/send.utils.test.js
+++ b/ui/pages/send/send.utils.test.js
@@ -290,7 +290,7 @@ describe('send utils', () => {
         if (typeof to === 'string' && to.match(/willFailBecauseOf:/u)) {
           throw new Error(to.match(/:(.+)$/u)[1]);
         }
-        return { toString: (n) => `0xabc${n}` };
+        return '0xabc16';
       }),
     };
     const baseexpectedCall = {