Don't search beyond Sync roots for highest priority work (#13335)

gaearon · web-flow · commit 3b3b7fcbbdc7 · 2018-08-07T01:59:18.000+01:00
diff --git a/packages/react-reconciler/src/ReactFiberScheduler.js b/packages/react-reconciler/src/ReactFiberScheduler.js
@@ -1841,6 +1841,11 @@ function findHighestPriorityRoot() {
         if (root === lastScheduledRoot) {
           break;
         }
+        if (highestPriorityWork === Sync) {
+          // Sync is highest priority by definition so
+          // we can stop searching.
+          break;
+        }
         previousScheduledRoot = root;
         root = root.nextScheduledRoot;
       }

Original file line number	Diff line number	Diff line change
`@@ -1841,6 +1841,11 @@ function findHighestPriorityRoot() {`
`1841`	`1841`	`if (root === lastScheduledRoot) {`
`1842`	`1842`	`break;`
`1843`	`1843`	`}`
	`1844`	`+ if (highestPriorityWork === Sync) {`
	`1845`	`+ // Sync is highest priority by definition so`
	`1846`	`+ // we can stop searching.`
	`1847`	`+ break;`
	`1848`	`+ }`
`1844`	`1849`	`previousScheduledRoot = root;`
`1845`	`1850`	`root = root.nextScheduledRoot;`
`1846`	`1851`	`}`