Merge pull request #26367 from overleaf/em-history-ot-undo

Fixes to TextOperation invert algorithm

GitOrigin-RevId: dd655660f6ecad7b6e9b2d4435dc9a5364d0fde2

libraries/overleaf-editor-core/test/range.test.js

@@ -1,4 +1,3 @@
-// @ts-check
 'use strict'
 
 const { expect } = require('chai')
@@ -449,4 +448,44 @@ describe('Range', function () {
       expect(() => range.insertAt(16, 3)).to.throw()
     })
   })
+
+  describe('intersect', function () {
+    it('should handle partially overlapping ranges', function () {
+      const range1 = new Range(5, 10)
+      const range2 = new Range(3, 6)
+      const intersection1 = range1.intersect(range2)
+      expect(intersection1.pos).to.equal(5)
+      expect(intersection1.length).to.equal(4)
+      const intersection2 = range2.intersect(range1)
+      expect(intersection2.pos).to.equal(5)
+      expect(intersection2.length).to.equal(4)
+    })
+
+    it('should intersect with itself', function () {
+      const range = new Range(5, 10)
+      const intersection = range.intersect(range)
+      expect(intersection.pos).to.equal(5)
+      expect(intersection.length).to.equal(10)
+    })
+
+    it('should handle nested ranges', function () {
+      const range1 = new Range(5, 10)
+      const range2 = new Range(7, 2)
+      const intersection1 = range1.intersect(range2)
+      expect(intersection1.pos).to.equal(7)
+      expect(intersection1.length).to.equal(2)
+      const intersection2 = range2.intersect(range1)
+      expect(intersection2.pos).to.equal(7)
+      expect(intersection2.length).to.equal(2)
+    })
+
+    it('should handle disconnected ranges', function () {
+      const range1 = new Range(5, 10)
+      const range2 = new Range(20, 30)
+      const intersection1 = range1.intersect(range2)
+      expect(intersection1).to.be.null
+      const intersection2 = range2.intersect(range1)
+      expect(intersection2).to.be.null
+    })
+  })
 })

libraries/overleaf-editor-core/test/text_operation.test.js

@@ -322,6 +322,47 @@ describe('TextOperation', function () {
         new TextOperation().retain(4).remove(4).retain(3)
       )
     })
+
+    it('undoing a tracked delete restores the tracked changes', function () {
+      expectInverseToLeadToInitialState(
+        new StringFileData(
+          'the quick brown fox jumps over the lazy dog',
+          undefined,
+          [
+            {
+              range: { pos: 5, length: 5 },
+              tracking: {
+                ts: '2023-01-01T00:00:00.000Z',
+                type: 'insert',
+                userId: 'user1',
+              },
+            },
+            {
+              range: { pos: 12, length: 3 },
+              tracking: {
+                ts: '2023-01-01T00:00:00.000Z',
+                type: 'delete',
+                userId: 'user1',
+              },
+            },
+            {
+              range: { pos: 18, length: 5 },
+              tracking: {
+                ts: '2023-01-01T00:00:00.000Z',
+                type: 'insert',
+                userId: 'user1',
+              },
+            },
+          ]
+        ),
+        new TextOperation()
+          .retain(7)
+          .retain(13, {
+            tracking: new TrackingProps('delete', 'user1', new Date()),
+          })
+          .retain(23)
+      )
+    })
   })
 
   describe('compose', function () {