Merge branch 'mylesj-feat/undomanager-doingstackitem'

package.json

@@ -12,9 +12,10 @@
     "url": "https://github.com/sponsors/dmonad"
   },
   "scripts": {
+    "clean": "rm -rf dist docs",
     "test": "npm run dist && node ./dist/tests.cjs --repetition-time 50",
     "test-extensive": "npm run lint && npm run dist && node ./dist/tests.cjs --production --repetition-time 10000",
-    "dist": "rm -rf dist && rollup -c && tsc",
+    "dist": "npm run clean && rollup -c && tsc",
     "watch": "rollup -wc",
     "lint": "markdownlint README.md && standard && tsc",
     "docs": "rm -rf docs; jsdoc --configure ./.jsdoc.json --verbose --readme ./README.md --package ./package.json || true",

src/utils/UndoManager.js

@@ -52,11 +52,6 @@ const clearUndoManagerStackItem = (tr, um, stackItem) => {
  * @return {StackItem?}
  */
 const popStackItem = (undoManager, stack, eventType) => {
-  /**
-   * Whether a change happened
-   * @type {StackItem?}
-   */
-  let result = null
   /**
    * Keep a reference to the transaction so we can fire the event with the changedParentTypes
    * @type {any}
@@ -65,7 +60,7 @@ const popStackItem = (undoManager, stack, eventType) => {
   const doc = undoManager.doc
   const scope = undoManager.scope
   transact(doc, transaction => {
-    while (stack.length > 0 && result === null) {
+    while (stack.length > 0 && undoManager.currStackItem === null) {
       const store = doc.store
       const stackItem = /** @type {StackItem} */ (stack.pop())
       /**
@@ -113,7 +108,7 @@ const popStackItem = (undoManager, stack, eventType) => {
           performedChange = true
         }
       }
-      result = performedChange ? stackItem : null
+      undoManager.currStackItem = performedChange ? stackItem : null
     }
     transaction.changed.forEach((subProps, type) => {
       // destroy search marker if necessary
@@ -123,11 +118,12 @@ const popStackItem = (undoManager, stack, eventType) => {
     })
     _tr = transaction
   }, undoManager)
-  if (result != null) {
+  if (undoManager.currStackItem != null) {
     const changedParentTypes = _tr.changedParentTypes
-    undoManager.emit('stack-item-popped', [{ stackItem: result, type: eventType, changedParentTypes }, undoManager])
+    undoManager.emit('stack-item-popped', [{ stackItem: undoManager.currStackItem, type: eventType, changedParentTypes }, undoManager])
+    undoManager.currStackItem = null
   }
-  return result
+  return undoManager.currStackItem
 }
 
 /**
@@ -191,6 +187,12 @@ export class UndoManager extends Observable {
      */
     this.undoing = false
     this.redoing = false
+    /**
+     * The currently popped stack item if UndoManager.undoing or UndoManager.redoing
+     *
+     * @type {StackItem|null}
+     */
+    this.currStackItem = null
     this.lastChange = 0
     this.ignoreRemoteMapChanges = ignoreRemoteMapChanges
     this.captureTimeout = captureTimeout

tests/undo-redo.tests.js

@@ -715,3 +715,33 @@ export const testUndoDeleteInMap = (tc) => {
   undoManager.undo()
   t.compare(map0.toJSON(), { a: 'a' })
 }
+
+/**
+ * It should expose the StackItem being processed if undoing
+ *
+ * @param {t.TestCase} _tc
+ */
+export const testUndoDoingStackItem = async (_tc) => {
+  const doc = new Y.Doc()
+  const text = doc.getText('text')
+  const undoManager = new Y.UndoManager([text])
+  undoManager.on('stack-item-added', /** @param {any} event */ event => {
+    event.stackItem.meta.set('str', '42')
+  })
+  let metaUndo = /** @type {any} */ (null)
+  let metaRedo = /** @type {any} */ (null)
+  text.observe((event) => {
+    const /** @type {Y.UndoManager} */ origin = event.transaction.origin
+    if (origin === undoManager && origin.undoing) {
+      metaUndo = origin.currStackItem?.meta.get('str')
+    } else if (origin === undoManager && origin.redoing) {
+      metaRedo = origin.currStackItem?.meta.get('str')
+    }
+  })
+  text.insert(0, 'abc')
+  undoManager.undo()
+  undoManager.redo()
+  t.compare(metaUndo, '42', 'currStackItem is accessible while undoing')
+  t.compare(metaRedo, '42', 'currStackItem is accessible while redoing')
+  t.compare(undoManager.currStackItem, null, 'currStackItem is null after observe/transaction')
+}