From ff831eba7d85d882af12c4fa6e05cd5ea576f6c9 Mon Sep 17 00:00:00 2001
From: themithy <11431578+themithy@users.noreply.github.com>
Date: Mon, 19 Aug 2019 18:37:38 +0200
Subject: [PATCH] Deduplicate dirty paths for normalization. (#2916)

* Deduplicate dirty paths for normalization.

* Update editor.js
---
 packages/slate/src/controllers/editor.js | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/slate/src/controllers/editor.js b/packages/slate/src/controllers/editor.js
index 5ef061a564..10bd3efcd0 100644
--- a/packages/slate/src/controllers/editor.js
+++ b/packages/slate/src/controllers/editor.js
@@ -107,7 +107,20 @@ class Editor {
       return transformed.toArray()
     })
 
-    this.tmp.dirty = Array.prototype.concat.apply(newDirtyPaths, dirty)
+    const pathIndex = {}
+    const dirtyPaths = Array.prototype.concat.apply(newDirtyPaths, dirty)
+    this.tmp.dirty = []
+
+    // PERF: De-dupe the paths so we don't do extra normalization.
+    dirtyPaths.forEach(dirtyPath => {
+      const key = dirtyPath.join(',')
+
+      if (!pathIndex[key]) {
+        this.tmp.dirty.push(dirtyPath)
+      }
+
+      pathIndex[key] = true
+    })
 
     // If we're not already, queue the flushing process on the next tick.
     if (!this.tmp.flushing) {