History: withNewBatch (#5747)

* feat

* Create gold-cheetahs-rest.md

* refactor

* fix

Author: zbeyens

.changeset/gold-cheetahs-rest.md

@@ -0,0 +1,5 @@
+---
+'slate-history': patch
+---
+
+Add `HistoryEditor.withNewBatch`

packages/slate-history/src/history-editor.ts

@@ -8,6 +8,7 @@ import { History } from './history'
 export const HISTORY = new WeakMap<Editor, History>()
 export const SAVING = new WeakMap<Editor, boolean | undefined>()
 export const MERGING = new WeakMap<Editor, boolean | undefined>()
+export const SPLITTING_ONCE = new WeakMap<Editor, boolean | undefined>()
 
 /**
  * `HistoryEditor` contains helpers for history-enabled editors.
@@ -38,6 +39,18 @@ export const HistoryEditor = {
     return MERGING.get(editor)
   },
 
+  /**
+   * Get the splitting once flag's current value.
+   */
+
+  isSplittingOnce(editor: HistoryEditor): boolean | undefined {
+    return SPLITTING_ONCE.get(editor)
+  },
+
+  setSplittingOnce(editor: HistoryEditor, value: boolean | undefined): void {
+    SPLITTING_ONCE.set(editor, value)
+  },
+
   /**
    * Get the saving flag's current value.
    */
@@ -73,6 +86,20 @@ export const HistoryEditor = {
     MERGING.set(editor, prev)
   },
 
+  /**
+   * Apply a series of changes inside a synchronous `fn`, ensuring that the first
+   * operation starts a new batch in the history. Subsequent operations will be
+   * merged as usual.
+   */
+  withNewBatch(editor: HistoryEditor, fn: () => void): void {
+    const prev = HistoryEditor.isMerging(editor)
+    MERGING.set(editor, true)
+    SPLITTING_ONCE.set(editor, true)
+    fn()
+    MERGING.set(editor, prev)
+    SPLITTING_ONCE.delete(editor)
+  },
+
   /**
    * Apply a series of changes inside a synchronous `fn`, without merging any of
    * the new operations into previous save point in the history.

packages/slate-history/src/with-history.ts

@@ -1,4 +1,4 @@
-import { Editor, Operation, Path, Range, Transforms } from 'slate'
+import { Editor, Operation, Path, Transforms } from 'slate'
 
 import { HistoryEditor } from './history-editor'
 
@@ -90,6 +90,11 @@ export const withHistory = <T extends Editor>(editor: T) => {
         }
       }
 
+      if (HistoryEditor.isSplittingOnce(e)) {
+        merge = false
+        HistoryEditor.setSplittingOnce(e, undefined)
+      }
+
       if (lastBatch && merge) {
         lastBatch.operations.push(op)
       } else {