From cca994c6a1f13dd0b64ad0a909b5209b10cc8609 Mon Sep 17 00:00:00 2001
From: Brian Vaughn <bvaughn@fb.com>
Date: Thu, 2 Jan 2020 14:44:07 -0800
Subject: [PATCH] DevTools Profiler commit selector wraps around (#17760)

I used to disable the <- and -> buttons when you reached the beginning or end of the profiler data. This can be kind of annoying though when you just want to get to the last commit, and I don't think there's a good reason to enforce it anyway, so I backed that change out. The buttons now wrap around at the beginning or end of the list.
---
 .../views/Profiler/SnapshotSelector.js        | 23 ++++++++-----------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/packages/react-devtools-shared/src/devtools/views/Profiler/SnapshotSelector.js b/packages/react-devtools-shared/src/devtools/views/Profiler/SnapshotSelector.js
index 5d9424211af8f..41979cee6b9f5 100644
--- a/packages/react-devtools-shared/src/devtools/views/Profiler/SnapshotSelector.js
+++ b/packages/react-devtools-shared/src/devtools/views/Profiler/SnapshotSelector.js
@@ -95,20 +95,20 @@ export default function SnapshotSelector(_: Props) {
 
   const viewNextCommit = useCallback(
     () => {
-      const nextCommitIndex = Math.min(
-        ((selectedFilteredCommitIndex: any): number) + 1,
-        filteredCommitIndices.length - 1,
-      );
+      let nextCommitIndex = ((selectedFilteredCommitIndex: any): number) + 1;
+      if (nextCommitIndex === filteredCommitIndices.length) {
+        nextCommitIndex = 0;
+      }
       selectCommitIndex(filteredCommitIndices[nextCommitIndex]);
     },
     [selectedFilteredCommitIndex, filteredCommitIndices, selectCommitIndex],
   );
   const viewPrevCommit = useCallback(
     () => {
-      const nextCommitIndex = Math.max(
-        ((selectedFilteredCommitIndex: any): number) - 1,
-        0,
-      );
+      let nextCommitIndex = ((selectedFilteredCommitIndex: any): number) - 1;
+      if (nextCommitIndex < 0) {
+        nextCommitIndex = filteredCommitIndices.length - 1;
+      }
       selectCommitIndex(filteredCommitIndices[nextCommitIndex]);
     },
     [selectedFilteredCommitIndex, filteredCommitIndices, selectCommitIndex],
@@ -141,7 +141,7 @@ export default function SnapshotSelector(_: Props) {
       <span className={styles.IndexLabel}>{label}</span>
       <Button
         className={styles.Button}
-        disabled={selectedFilteredCommitIndex === 0 || numFilteredCommits === 0}
+        disabled={numFilteredCommits === 0}
         onClick={viewPrevCommit}
         title="Select previous commit">
         <ButtonIcon type="previous" />
@@ -173,10 +173,7 @@ export default function SnapshotSelector(_: Props) {
       </div>
       <Button
         className={styles.Button}
-        disabled={
-          selectedFilteredCommitIndex === null ||
-          selectedFilteredCommitIndex >= numFilteredCommits - 1
-        }
+        disabled={numFilteredCommits === 0}
         onClick={viewNextCommit}
         title="Select next commit">
         <ButtonIcon type="next" />