adding more sanity checkss to yarray.tests

src/utils/ListIterator.js

@@ -122,8 +122,17 @@ export class ListIterator {
       len += this.rel
       this.rel = 0
     }
-    while (item && !this.reachedEnd && (len > 0 || (len === 0 && (!item.countable || item.deleted || item === this.currMoveEnd || item.moved !== this.currMove)))) {
-      if (item.countable && !item.deleted && item.moved === this.currMove && len > 0) {
+    while ((!this.reachedEnd || this.currMove !== null) && (len > 0 || (len === 0 && item && (!item.countable || item.deleted || item === this.currMoveEnd || (this.reachedEnd && this.currMoveEnd === null) || item.moved !== this.currMove)))) {
+      if (item === this.currMoveEnd || (this.currMoveEnd === null && this.reachedEnd && this.currMove)) {
+        item = /** @type {Item} */ (this.currMove) // we iterate to the right after the current condition
+        const { start, end, move } = this.movedStack.pop() || { start: null, end: null, move: null }
+        this.currMove = move
+        this.currMoveStart = start
+        this.currMoveEnd = end
+        this.reachedEnd = false
+      } else if (item === null) {
+        break
+      } else if (item.countable && !item.deleted && item.moved === this.currMove && len > 0) {
         len -= item.length
         if (len < 0) {
           this.rel = item.length + len
@@ -141,13 +150,6 @@ export class ListIterator {
         item = start
         continue
       }
-      if (item === this.currMoveEnd) {
-        item = /** @type {Item} */ (this.currMove) // we iterate to the right after the current condition
-        const { start, end, move } = this.movedStack.pop() || { start: null, end: null, move: null }
-        this.currMove = move
-        this.currMoveStart = start
-        this.currMoveEnd = end
-      }
       if (item.right) {
         item = item.right
       } else {
@@ -159,6 +161,23 @@ export class ListIterator {
     return this
   }
 
+  /**
+   * @param {Transaction} tr
+   */
+  reduceMoves (tr) {
+    let item = this.nextItem
+    if (item !== null) {
+      while (item === this.currMoveStart) {
+        item = /** @type {Item} */ (this.currMove) // we iterate to the left after the current condition
+        const { start, end, move } = this.movedStack.pop() || { start: null, end: null, move: null }
+        this.currMove = move
+        this.currMoveStart = start
+        this.currMoveEnd = end
+      }
+      this.nextItem = item
+    }
+  }
+
   /**
    * @param {Transaction} tr
    * @param {number} len
@@ -249,7 +268,7 @@ export class ListIterator {
           this.reachedEnd = true
         }
       }
-      if (this.nextItem && !this.reachedEnd && len > 0) {
+      if (this.nextItem && (!this.reachedEnd || this.currMove !== null) && len > 0) {
         this.forward(tr, 0)
       }
     }
@@ -317,6 +336,7 @@ export class ListIterator {
    * @param {Array<AbstractContent>} content
    */
   insertContents (tr, content) {
+    this.reduceMoves(tr)
     this._splitRel(tr)
     const parent = this.type
     const store = tr.doc.store

src/utils/RelativePosition.js

@@ -75,6 +75,10 @@ export class RelativePosition {
      */
     this.assoc = assoc
   }
+
+  clone () {
+    return new RelativePosition(this.type, this.tname, this.item, this.assoc)
+  }
 }
 
 /**

src/utils/YEvent.js

@@ -213,7 +213,7 @@ export class YEvent {
                 continue // do not move to item.right
               }
             } else if (item.moved !== currMove) {
-              if (!currMoveIsNew && item.countable && !this.adds(item) && (this.transaction.prevMoved.get(item) || null) === currMove) {
+              if (!currMoveIsNew && item.countable && item.moved && !this.adds(item) && !this.adds(item.moved) && (this.transaction.prevMoved.get(item) || null) === currMove) {
                 if (lastOp === null || lastOp.delete === undefined) {
                   packOp()
                   lastOp = { delete: 0 }

src/utils/updates.js

@@ -308,6 +308,7 @@ export const mergeUpdatesV2 = (updates, YDecoder = UpdateDecoderV2, YEncoder = U
   // Note: Should handle that some operations cannot be applied yet ()
 
   while (true) {
+    // @todo this incurs an exponential overhead. We could instead only sort the item that changed.
     // Write higher clients first ⇒ sort by clientID & clock and remove decoders without content
     lazyStructDecoders = lazyStructDecoders.filter(dec => dec.curr !== null)
     lazyStructDecoders.sort(