Merge pull request #393 from dkuhnert/issue-392

cleanup redundant text attributes when delete attributes

src/types/YText.js

@@ -291,7 +291,8 @@ const formatText = (transaction, parent, currPos, length, attributes) => {
   const negatedAttributes = insertAttributes(transaction, parent, currPos, attributes)
   // iterate until first non-format or null is found
   // delete all formats with attributes[format.key] != null
-  while (length > 0 && currPos.right !== null) {
+  // also check the attributes after the first non-format as we do not want to insert redundant negated attributes there
+  while (currPos.right !== null && (length > 0 || currPos.right.content.constructor === ContentFormat)) {
     if (!currPos.right.deleted) {
       switch (currPos.right.content.constructor) {
         case ContentFormat: {

tests/undo-redo.tests.js

@@ -527,3 +527,41 @@ export const testUndoBlockBug = tc => {
   undoManager.redo() // {"text":{}}
   t.compare(design.toJSON(), { text: { blocks: { text: '4' } } })
 }
+
+/**
+ * Undo text formatting delete should not corrupt peer state.
+ * 
+ * @see https://github.com/yjs/yjs/issues/392
+ * @param {t.TestCase} tc
+ */
+export const testUndoDeleteTextFormat = tc => {
+  const doc = new Y.Doc()
+  const text = doc.getText()
+  text.insert(0, 'Attack ships on fire off the shoulder of Orion.')
+  const doc2 = new Y.Doc()
+  const text2 = doc2.getText();
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+  const undoManager = new Y.UndoManager(text)
+
+  text.format(13, 7, { bold: true })
+  undoManager.stopCapturing()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  text.format(16, 4, { bold: null })
+  undoManager.stopCapturing()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  undoManager.undo()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  const expect = [
+    { insert: 'Attack ships ' },
+    {
+      insert: 'on fire',
+      attributes: { bold: true }
+    },
+    { insert: ' off the shoulder of Orion.' }
+  ]
+  t.compare(text.toDelta(), expect)
+  t.compare(text2.toDelta(), expect)
+}

tests/y-text.tests.js

@@ -607,6 +607,35 @@ export const testFormattingBug = async tc => {
   console.log(text1.toDelta())
 }
 
+/**
+ * Delete formatting should not leave redundant formatting items.
+ *
+ * @param {t.TestCase} tc
+ */
+export const testDeleteFormatting = tc => {
+  const doc = new Y.Doc()
+  const text = doc.getText()
+  text.insert(0, 'Attack ships on fire off the shoulder of Orion.')
+
+  const doc2 = new Y.Doc()
+  const text2 = doc2.getText()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  text.format(13, 7, { bold: true })
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  text.format(16, 4, { bold: null })
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  const expected = [
+    { insert: 'Attack ships ' },
+    { insert: 'on ', attributes: { bold: true } },
+    { insert: 'fire off the shoulder of Orion.' }
+  ]
+  t.compare(text.toDelta(), expected)
+  t.compare(text2.toDelta(), expected)
+}
+
 // RANDOM TESTS
 
 let charCounter = 0