Use native character insertion to fix browser/OS text features (#3888)

* use native character insertion to fix browser/OS text features. (flickering spellcheck, autocorrect, text shortcuts, etc.)

move some checks into previous if statement, remove commented out code

move native behavior into `slate-react`, and remove any external interface

dont use native editing if marks are set, as a new node will be inserted

match -> above

remove nativeOperationsQueue from editor

bail out of native queueing and immediately flush events if non insert_text operation is being applied.

* Convert TextString to a functional component

* Batch normalization of native op application

* Add changeset

* only proceed as native event if single character non-special character or space, to limit potential bad side effects.

* Revert "fix ime double input with mark"

* Comment wording tweak

Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

* Comment wording tweak

Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

* Comment wording tweak

Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

* Comment wording tweak

Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

* Comment wording tweak

Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

Co-authored-by: Ludwig Pettersson <luddep@gmail.com>
Co-authored-by: Dylan Schiemann <dylan@dojotoolkit.org>

.changeset/mighty-zebras-relax.md

@@ -0,0 +1,5 @@
+---
+'slate-react': minor
+---
+
+Use native character insertion to fix browser/OS text features

packages/slate-react/src/components/editable.tsx

@@ -47,6 +47,7 @@ import {
   PLACEHOLDER_SYMBOL,
   EDITOR_TO_WINDOW,
 } from '../utils/weak-maps'
+import { asNative, flushNativeEvents } from '../utils/native'
 
 const Children = (props: Parameters<typeof useChildren>[0]) => (
   <React.Fragment>{useChildren(props)}</React.Fragment>
@@ -267,7 +268,49 @@ export const Editable = (props: EditableProps) => {
           return
         }
 
-        event.preventDefault()
+        let native = false
+        if (
+          type === 'insertText' &&
+          selection &&
+          Range.isCollapsed(selection) &&
+          // Only use native character insertion for single characters a-z or space for now.
+          // Long-press events (hold a + press 4 = ä) to choose a special character otherwise
+          // causes duplicate inserts.
+          event.data &&
+          event.data.length === 1 &&
+          /[a-z ]/i.test(event.data) &&
+          // Chrome seems to have issues correctly editing the start of nodes.
+          // When there is an inline element, e.g. a link, and you select
+          // right after it (the start of the next node).
+          selection.anchor.offset !== 0
+        ) {
+          native = true
+
+          // Skip native if there are marks, as
+          // `insertText` will insert a node, not just text.
+          if (editor.marks) {
+            native = false
+          }
+
+          // and because of the selection moving in `insertText` (create-editor.ts).
+          const { anchor } = selection
+          const inline = Editor.above(editor, {
+            at: anchor,
+            match: n => Editor.isInline(editor, n),
+            mode: 'highest',
+          })
+          if (inline) {
+            const [, inlinePath] = inline
+
+            if (Editor.isEnd(editor, selection.anchor, inlinePath)) {
+              native = false
+            }
+          }
+        }
+
+        if (!native) {
+          event.preventDefault()
+        }
 
         // COMPAT: For the deleting forward/backward input types we don't want
         // to change the selection because it is the range that will be deleted,
@@ -379,7 +422,13 @@ export const Editable = (props: EditableProps) => {
             if (data instanceof window.DataTransfer) {
               ReactEditor.insertData(editor, data as DataTransfer)
             } else if (typeof data === 'string') {
-              Editor.insertText(editor, data)
+              // Only insertText operations use the native functionality, for now.
+              // Potentially expand to single character deletes, as well.
+              if (native) {
+                asNative(editor, () => Editor.insertText(editor, data))
+              } else {
+                Editor.insertText(editor, data)
+              }
             }
 
             break
@@ -551,6 +600,13 @@ export const Editable = (props: EditableProps) => {
             },
             [readOnly]
           )}
+          onInput={useCallback((event: React.SyntheticEvent) => {
+            // Flush native operations, as native events will have propogated
+            // and we can correctly compare DOM text values in components
+            // to stop rendering, so that browser functions like autocorrect
+            // and spellcheck work as expected.
+            flushNativeEvents(editor)
+          }, [])}
           onBlur={useCallback(
             (event: React.FocusEvent<HTMLDivElement>) => {
               if (

packages/slate-react/src/components/leaf.tsx

@@ -4,9 +4,6 @@ import String from './string'
 import { PLACEHOLDER_SYMBOL } from '../utils/weak-maps'
 import { RenderLeafProps, RenderPlaceholderProps } from './editable'
 
-// auto-incrementing key for String component, force it refresh to
-// prevent inconsistent rendering by React with IME input
-let keyForString = 0
 /**
  * Individual leaves in a text node with unique formatting.
  */
@@ -48,13 +45,7 @@ const Leaf = (props: {
   }, [placeholderRef, leaf])
 
   let children = (
-    <String
-      key={keyForString++}
-      isLast={isLast}
-      leaf={leaf}
-      parent={parent}
-      text={text}
-    />
+    <String isLast={isLast} leaf={leaf} parent={parent} text={text} />
   )
 
   if (leaf[PLACEHOLDER_SYMBOL]) {

packages/slate-react/src/components/string.tsx

@@ -1,4 +1,4 @@
-import React from 'react'
+import React, { useRef } from 'react'
 import { Editor, Text, Path, Element, Node } from 'slate'
 
 import { ReactEditor, useSlateStatic } from '..'
@@ -55,16 +55,32 @@ const String = (props: {
 /**
  * Leaf strings with text in them.
  */
+const TextString = React.memo(
+  (props: { text: string; isTrailing?: boolean }) => {
+    const { text, isTrailing = false } = props
 
-const TextString = (props: { text: string; isTrailing?: boolean }) => {
-  const { text, isTrailing = false } = props
-  return (
-    <span data-slate-string>
-      {text}
-      {isTrailing ? '\n' : null}
-    </span>
-  )
-}
+    const ref = useRef<HTMLSpanElement>(null)
+    const forceUpdateFlag = useRef(false)
+
+    if (ref.current && ref.current.textContent !== text) {
+      forceUpdateFlag.current = !forceUpdateFlag.current
+    }
+
+    // This component may have skipped rendering due to native operations being
+    // applied. If an undo is performed React will see the old and new shadow DOM
+    // match and not apply an update. Forces each render to actually reconcile.
+    return (
+      <span
+        data-slate-string
+        ref={ref}
+        key={forceUpdateFlag.current ? 'A' : 'B'}
+      >
+        {text}
+        {isTrailing ? '\n' : null}
+      </span>
+    )
+  }
+)
 
 /**
  * Leaf strings without text, render as zero-width strings.

packages/slate-react/src/plugin/with-react.ts

@@ -4,6 +4,11 @@ import { Editor, Node, Path, Operation, Transforms, Range } from 'slate'
 import { ReactEditor } from './react-editor'
 import { Key } from '../utils/key'
 import { EDITOR_TO_ON_CHANGE, NODE_TO_KEY } from '../utils/weak-maps'
+import {
+  AS_NATIVE,
+  NATIVE_OPERATIONS,
+  flushNativeEvents,
+} from '../utils/native'
 import { isDOMText, getPlainText } from '../utils/dom'
 import { findCurrentLineRange } from '../utils/lines'
 
@@ -49,6 +54,31 @@ export const withReact = <T extends Editor>(editor: T) => {
   }
 
   e.apply = (op: Operation) => {
+    // if we're NOT an insert_text and there's a queue
+    // of native events, bail out and flush the queue.
+    // otherwise transforms as part of this cycle will
+    // be incorrect.
+    //
+    // This is needed as overriden operations (e.g. `insertText`)
+    // can call additional transforms, which will need accurate
+    // content, and will be called _before_ `onInput` is fired.
+    if (op.type !== 'insert_text') {
+      AS_NATIVE.set(editor, false)
+      flushNativeEvents(editor)
+    }
+
+    // If we're in native mode, queue the operation
+    // and it will be applied later.
+    if (AS_NATIVE.get(editor)) {
+      const nativeOps = NATIVE_OPERATIONS.get(editor)
+      if (nativeOps) {
+        nativeOps.push(op)
+      } else {
+        NATIVE_OPERATIONS.set(editor, [op])
+      }
+      return
+    }
+
     const matches: [Path, Key][] = []
 
     switch (op.type) {

packages/slate-react/src/utils/native.ts

@@ -0,0 +1,37 @@
+import { Editor, Operation } from 'slate'
+
+export const AS_NATIVE: WeakMap<Editor, boolean> = new WeakMap()
+export const NATIVE_OPERATIONS: WeakMap<Editor, Operation[]> = new WeakMap()
+
+/**
+ * `asNative` queues operations as native, meaning native browser events will
+ * not have been prevented, and we need to flush the operations
+ * after the native events have propogated to the DOM.
+ * @param {Editor} editor - Editor on which the operations are being applied
+ * @param {callback} fn - Function containing .exec calls which will be queued as native
+ */
+export const asNative = (editor: Editor, fn: () => void) => {
+  AS_NATIVE.set(editor, true)
+  fn()
+  AS_NATIVE.set(editor, false)
+}
+
+/**
+ * `flushNativeEvents` applies any queued native events.
+ * @param {Editor} editor - Editor on which the operations are being applied
+ */
+export const flushNativeEvents = (editor: Editor) => {
+  const nativeOps = NATIVE_OPERATIONS.get(editor)
+
+  // Clear list _before_ applying, as we might flush
+  // events in each op, as well.
+  NATIVE_OPERATIONS.set(editor, [])
+
+  if (nativeOps) {
+    Editor.withoutNormalizing(editor, () => {
+      nativeOps.forEach(op => {
+        editor.apply(op)
+      })
+    })
+  }
+}