Avoid transforming dirty paths if the op won't touch them (#4735)

* Avoid transforming dirty paths if the op won't touch them

* Avoid the loop entirely if op doesn't affect path

.changeset/two-coins-enjoy.md

@@ -0,0 +1,5 @@
+---
+'slate': patch
+---
+
+Optimize path transforms during normalization

packages/slate/src/create-editor.ts

@@ -13,7 +13,7 @@ import {
   Text,
   Transforms,
 } from './'
-import { DIRTY_PATHS, FLUSHING } from './utils/weak-maps'
+import { DIRTY_PATHS, DIRTY_PATH_KEYS, FLUSHING } from './utils/weak-maps'
 
 /**
  * Create a new Slate `Editor` object.
@@ -42,33 +42,41 @@ export const createEditor = (): Editor => {
         RangeRef.transform(ref, op)
       }
 
-      const set = new Set()
-      const dirtyPaths: Path[] = []
+      const oldDirtyPaths = DIRTY_PATHS.get(editor) || []
+      const oldDirtyPathKeys = DIRTY_PATH_KEYS.get(editor) || new Set()
+      let dirtyPaths: Path[]
+      let dirtyPathKeys: Set<string>
 
       const add = (path: Path | null) => {
         if (path) {
           const key = path.join(',')
 
-          if (!set.has(key)) {
-            set.add(key)
+          if (!dirtyPathKeys.has(key)) {
+            dirtyPathKeys.add(key)
             dirtyPaths.push(path)
           }
         }
       }
 
-      const oldDirtyPaths = DIRTY_PATHS.get(editor) || []
-      const newDirtyPaths = getDirtyPaths(op)
-
-      for (const path of oldDirtyPaths) {
-        const newPath = Path.transform(path, op)
-        add(newPath)
+      if (Path.operationCanTransformPath(op)) {
+        dirtyPaths = []
+        dirtyPathKeys = new Set()
+        for (const path of oldDirtyPaths) {
+          const newPath = Path.transform(path, op)
+          add(newPath)
+        }
+      } else {
+        dirtyPaths = oldDirtyPaths
+        dirtyPathKeys = oldDirtyPathKeys
       }
 
+      const newDirtyPaths = getDirtyPaths(op)
       for (const path of newDirtyPaths) {
         add(path)
       }
 
       DIRTY_PATHS.set(editor, dirtyPaths)
+      DIRTY_PATH_KEYS.set(editor, dirtyPathKeys)
       Transforms.transform(editor, op)
       editor.operations.push(op)
       Editor.normalize(editor)

packages/slate/src/interfaces/editor.ts

@@ -19,6 +19,7 @@ import {
 } from '..'
 import {
   DIRTY_PATHS,
+  DIRTY_PATH_KEYS,
   NORMALIZING,
   PATH_REFS,
   POINT_REFS,
@@ -979,13 +980,26 @@ export const Editor: EditorInterface = {
       return DIRTY_PATHS.get(editor) || []
     }
 
+    const getDirtyPathKeys = (editor: Editor) => {
+      return DIRTY_PATH_KEYS.get(editor) || new Set()
+    }
+
+    const popDirtyPath = (editor: Editor): Path => {
+      const path = getDirtyPaths(editor).pop()!
+      const key = path.join(',')
+      getDirtyPathKeys(editor).delete(key)
+      return path
+    }
+
     if (!Editor.isNormalizing(editor)) {
       return
     }
 
     if (force) {
       const allPaths = Array.from(Node.nodes(editor), ([, p]) => p)
+      const allPathKeys = new Set(allPaths.map(p => p.join(',')))
       DIRTY_PATHS.set(editor, allPaths)
+      DIRTY_PATH_KEYS.set(editor, allPathKeys)
     }
 
     if (getDirtyPaths(editor).length === 0) {
@@ -1026,7 +1040,7 @@ export const Editor: EditorInterface = {
           `)
         }
 
-        const dirtyPath = getDirtyPaths(editor).pop()!
+        const dirtyPath = popDirtyPath(editor)
 
         // If the node doesn't exist in the tree, it does not need to be normalized.
         if (Node.has(editor, dirtyPath)) {

packages/slate/src/interfaces/path.ts

@@ -34,6 +34,7 @@ export interface PathInterface {
     }
   ) => Path[]
   next: (path: Path) => Path
+  operationCanTransformPath: (operation: Operation) => boolean
   parent: (path: Path) => Path
   previous: (path: Path) => Path
   relative: (path: Path, ancestor: Path) => Path
@@ -291,6 +292,26 @@ export const Path: PathInterface = {
     return path.slice(0, -1).concat(last + 1)
   },
 
+  /**
+   * Returns whether this operation can affect paths or not. Used as an
+   * optimization when updating dirty paths during normalization
+   *
+   * NOTE: This *must* be kept in sync with the implementation of 'transform'
+   * below
+   */
+  operationCanTransformPath(operation: Operation): boolean {
+    switch (operation.type) {
+      case 'insert_node':
+      case 'remove_node':
+      case 'merge_node':
+      case 'split_node':
+      case 'move_node':
+        return true
+      default:
+        return false
+    }
+  },
+
   /**
    * Given a path, return a new path referring to the parent node above it.
    */

packages/slate/src/utils/weak-maps.ts

@@ -1,6 +1,7 @@
 import { Editor, Path, PathRef, PointRef, RangeRef } from '..'
 
 export const DIRTY_PATHS: WeakMap<Editor, Path[]> = new WeakMap()
+export const DIRTY_PATH_KEYS: WeakMap<Editor, Set<string>> = new WeakMap()
 export const FLUSHING: WeakMap<Editor, boolean> = new WeakMap()
 export const NORMALIZING: WeakMap<Editor, boolean> = new WeakMap()
 export const PATH_REFS: WeakMap<Editor, Set<PathRef>> = new WeakMap()