TypeCellOS · nperez0111 · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026
diff --git a/packages/core/src/api/blockManipulation/commands/moveBlocks/moveBlocks.ts b/packages/core/src/api/blockManipulation/commands/moveBlocks/moveBlocks.ts
@@ -241,7 +241,7 @@ function getMoveUpPlacement(
       placement = "before";
     }
   } else if (prevBlock.children.length > 0) {
-    referenceBlock = prevBlock.children[prevBlock.children.length - 1];
+    referenceBlock = prevBlock.children.at(-1);
     placement = "after";
   } else {
     referenceBlock = prevBlock;
@@ -377,8 +377,7 @@ export function moveBlocksDown(
     } else {
       const selection = editor.getSelection();
       sourceBlock =
-        selection?.blocks[selection?.blocks.length - 1] ||
-        editor.getTextCursorPosition().block;
+        selection?.blocks.at(-1) || editor.getTextCursorPosition().block;
     }
 
     const moveDownPlacement = getMoveDownPlacement(

diff --git a/packages/core/src/api/blockManipulation/commands/updateBlock/updateBlock.test.ts b/packages/core/src/api/blockManipulation/commands/updateBlock/updateBlock.test.ts
@@ -972,7 +972,7 @@ describe("Test updateBlock minimal steps", () => {
     expect(block.props.level).toBe(3);
     // The styled text on either side of the replaced range is preserved.
     expect(block.content[0].text).toBe("Paragraph");
-    expect(block.content[block.content.length - 1].text).toBe("content");
+    expect(block.content.at(-1)?.text).toBe("content");
     expect(() => editor._tiptapEditor.state.doc.check()).not.toThrow();
   });
 });
diff --git a/packages/core/src/api/blockManipulation/tables/tables.test.ts b/packages/core/src/api/blockManipulation/tables/tables.test.ts
@@ -1762,11 +1762,12 @@ describe("Test cropEmptyRowsOrColumns", () => {
           ...simpleTable,
           content: {
             ...simpleTable.content,
-            rows: simpleTable.content.rows.concat([
+            rows: [
+              ...simpleTable.content.rows,
               {
                 cells: [emptyCell, emptyCell],
               },
-            ]),
+            ],
           },
         },
         "rows",
@@ -1794,11 +1795,12 @@ describe("Test cropEmptyRowsOrColumns", () => {
           ...tableWithColspan,
           content: {
             ...tableWithColspan.content,
-            rows: tableWithColspan.content.rows.concat([
+            rows: [
+              ...tableWithColspan.content.rows,
               {
                 cells: [emptyCell, emptyCell, emptyCell],
               },
-            ]),
+            ],
           },
         },
         "rows",
@@ -1835,11 +1837,12 @@ describe("Test cropEmptyRowsOrColumns", () => {
           ...tableWithRowspan,
           content: {
             ...tableWithRowspan.content,
-            rows: tableWithRowspan.content.rows.concat([
+            rows: [
+              ...tableWithRowspan.content.rows,
               {
                 cells: [emptyCell, emptyCell, emptyCell],
               },
-            ]),
+            ],
           },
         },
         "rows",
@@ -1879,11 +1882,12 @@ describe("Test cropEmptyRowsOrColumns", () => {
           ...tableWithColspanAndRowspan,
           content: {
             ...tableWithColspanAndRowspan.content,
-            rows: tableWithColspanAndRowspan.content.rows.concat([
+            rows: [
+              ...tableWithColspanAndRowspan.content.rows,
               {
                 cells: [emptyCell, emptyCell, emptyCell],
               },
-            ]),
+            ],
           },
         },
         "rows",
@@ -1932,11 +1936,12 @@ describe("Test cropEmptyRowsOrColumns", () => {
           ...tableWithComplexRowspansAndColspans,
           content: {
             ...tableWithComplexRowspansAndColspans.content,
-            rows: tableWithComplexRowspansAndColspans.content.rows.concat([
+            rows: [
+              ...tableWithComplexRowspansAndColspans.content.rows,
               {
                 cells: [emptyCell, emptyCell, emptyCell, emptyCell],
               },
-            ]),
+            ],
           },
         },
         "rows",

diff --git a/packages/core/src/api/getBlockInfoFromPos.ts b/packages/core/src/api/getBlockInfoFromPos.ts
@@ -142,10 +142,13 @@ export function getNearestBlockPos(doc: Node, pos: number) {
   // eslint-disable-next-line no-console
   console.warn(`Position ${pos} is not within a blockContainer node.`);
 
-  const resolvedPos = doc.resolve(
-    allBlockContainerPositions.find((position) => position >= pos) ||
-      allBlockContainerPositions[allBlockContainerPositions.length - 1],
-  );
+  const blockPosition =
+    allBlockContainerPositions.find((position) => position >= pos) ??
+    allBlockContainerPositions.at(-1);
+  if (blockPosition === undefined) {
+    throw new Error("Document has no block containers");
+  }
+  const resolvedPos = doc.resolve(blockPosition);
   return {
     posBeforeNode: resolvedPos.pos,
     node: resolvedPos.nodeAfter!,

diff --git a/packages/core/src/api/getBlocksChangedByTransaction.ts b/packages/core/src/api/getBlocksChangedByTransaction.ts
@@ -270,7 +270,7 @@ function detectReorderedChildren(
   }
 
   const lisIndexSet = new Set<number>();
-  let k = tailsEndsAtIndex[tailsEndsAtIndex.length - 1] ?? -1;
+  let k = tailsEndsAtIndex.at(-1) ?? -1;
   while (k !== -1) {
     lisIndexSet.add(k);
     k = previousIndexInLis[k];

diff --git a/packages/core/src/api/nodeConversions/nodeToBlock.ts b/packages/core/src/api/nodeConversions/nodeToBlock.ts
@@ -58,9 +58,7 @@ export function contentNodeToTableContent<
     if (rowIndex === 0) {
       rowNode.content.forEach((cellNode) => {
         let colWidth = cellNode.attrs.colwidth as null | undefined | number[];
-        if (colWidth === undefined || colWidth === null) {
-          colWidth = new Array(cellNode.attrs.colspan ?? 1).fill(undefined);
-        }
+        colWidth ??= new Array(cellNode.attrs.colspan ?? 1).fill(undefined);
         ret.columnWidths.push(...colWidth);
       });
     }
@@ -81,11 +79,10 @@ export function contentNodeToTableContent<
         // If the schema only allowed a single tableParagraph node, then the merging would not work and cause prosemirror to fit the content into a new cell
         .reduce(
           (acc, contentPartial) => {
-            if (!acc.length) {
+            const last = acc.at(-1);
+            if (!last) {
               return contentPartial;
             }
-
-            const last = acc[acc.length - 1];
             const first = contentPartial[0];
 
             // Only merge if the last and first content are both styled text nodes and have the same styles
@@ -160,8 +157,11 @@ export function contentNodeToInlineContent<
           currentContent.text += "\n";
         } else if (isLinkInlineContent(currentContent)) {
           // Current content is a link.
-          currentContent.content[currentContent.content.length - 1].text +=
-            "\n";
+          const lastContent = currentContent.content.at(-1);
+          if (!lastContent) {
+            throw new Error("Link content is unexpectedly empty");
+          }
+          lastContent.text += "\n";
         } else {
           throw new Error("unexpected");
         }
@@ -263,15 +263,13 @@ export function contentNodeToInlineContent<
           // Node is a link (same type as current content).
           // Link URLs are the same.
           if (currentContent.href === linkMark.attrs.href) {
+            const lastContent = currentContent.content.at(-1);
+            if (!lastContent) {
+              throw new Error("Link content is unexpectedly empty");
+            }
             // Styles are the same.
-            if (
-              JSON.stringify(
-                currentContent.content[currentContent.content.length - 1]
-                  .styles,
-              ) === JSON.stringify(styles)
-            ) {
-              currentContent.content[currentContent.content.length - 1].text +=
-                node.textContent;
+            if (JSON.stringify(lastContent.styles) === JSON.stringify(styles)) {
+              lastContent.text += node.textContent;
             } else {
               // Styles are different.
               currentContent.content.push({

diff --git a/packages/core/src/api/parsers/markdown/markdownToHtml.ts b/packages/core/src/api/parsers/markdown/markdownToHtml.ts
@@ -293,7 +293,7 @@ function parseInlineCode(
         if (
           code.length >= 2 &&
           code[0] === " " &&
-          code[code.length - 1] === " " &&
+          code.at(-1) === " " &&
           /[^ ]/.test(code)
         ) {
           code = code.substring(1, code.length - 1);
@@ -762,7 +762,7 @@ function tokenize(markdown: string): Token[] {
     // Horizontal rule: ---, ***, ___ (3+ chars, optionally with spaces)
     if (/^(\s{0,3})([-*_])\s*(\2\s*){2,}$/.test(line)) {
       // Setext H2: --- immediately after a paragraph (no blank line between)
-      const prevToken = tokens[tokens.length - 1];
+      const prevToken = tokens.at(-1);
       if (
         !prevLineWasBlank &&
         line.trim().match(/^-+$/) &&

diff --git a/packages/core/src/blocks/ListItem/NumberedListItem/IndexingPlugin.ts b/packages/core/src/blocks/ListItem/NumberedListItem/IndexingPlugin.ts
@@ -75,7 +75,7 @@ function calculateListItemIndex(
   let isFirst: boolean;
 
   // Determine starting index from the block just before the chain
-  const lastInChain = chain[chain.length - 1];
+  const lastInChain = chain.at(-1) ?? { node, pos };
   const lastInfo = getBlockInfo({
     posBeforeNode: lastInChain.pos,
     node: lastInChain.node,

diff --git a/packages/core/src/comments/threadstore/TipTapThreadStore.ts b/packages/core/src/comments/threadstore/TipTapThreadStore.ts
@@ -79,9 +79,13 @@ export class TiptapThreadStore extends ThreadStore {
       },
     });
 
-    return this.tiptapCommentToCommentData(
-      thread.comments[thread.comments.length - 1],
-    );
+    const lastComment = thread.comments.at(-1);
+    if (!lastComment) {
+      throw new Error(
+        "Comment provider returned an empty thread after adding a comment",
+      );
+    }
+    return this.tiptapCommentToCommentData(lastComment);
   }
 
   /**

diff --git a/packages/core/src/editor/managers/BlockManager.ts b/packages/core/src/editor/managers/BlockManager.ts
@@ -130,9 +130,7 @@ export class BlockManager<
           return false;
         }
 
-        const children = reverse
-          ? block.children.slice().reverse()
-          : block.children;
+        const children = reverse ? block.children.toReversed() : block.children;
 
         if (!traverseBlockArray(children)) {
           return false;

diff --git a/packages/core/src/editor/managers/ExtensionManager/index.ts b/packages/core/src/editor/managers/ExtensionManager/index.ts
@@ -322,9 +322,9 @@ export class ExtensionManager {
     }
 
     // ---- Add phase (no updatePlugins call) ----
-    const newExtensions = ([] as (Extension | ExtensionFactoryInstance)[])
-      .concat(toRegister)
-      .filter(Boolean) as (Extension | ExtensionFactoryInstance)[];
+    const newExtensions = (
+      Array.isArray(toRegister) ? toRegister : [toRegister]
+    ).filter(Boolean) as (Extension | ExtensionFactoryInstance)[];
 
     const registeredExtensions = newExtensions
       .map((ext) => this.addExtension(ext))

diff --git a/packages/core/src/editor/transformPasted.ts b/packages/core/src/editor/transformPasted.ts
@@ -72,12 +72,9 @@ export function wrapTableRows(f: Fragment, schema: Schema) {
   const newItems: any[] = [];
   for (let i = 0; i < f.childCount; i++) {
     if (f.child(i).type.name === "tableRow") {
-      if (
-        newItems.length > 0 &&
-        newItems[newItems.length - 1].type.name === "table"
-      ) {
+      const prevTable = newItems.at(-1);
+      if (prevTable?.type.name === "table") {
         // append to existing table
-        const prevTable = newItems[newItems.length - 1];
         const newTable = prevTable.copy(prevTable.content.addToEnd(f.child(i)));
         newItems[newItems.length - 1] = newTable;
       } else {

diff --git a/packages/core/src/extensions/SideMenu/SideMenu.ts b/packages/core/src/extensions/SideMenu/SideMenu.ts
@@ -354,9 +354,7 @@ export class SideMenuView<
             ? coords.clientY - rect.bottom
             : 0;
 
-      const distance = Math.sqrt(
-        Math.pow(distanceX, 2) + Math.pow(distanceY, 2),
-      );
+      const distance = Math.sqrt(distanceX ** 2 + distanceY ** 2);
 
       if (distance < minDistance) {
         minDistance = distance;

diff --git a/packages/core/src/extensions/Versioning/Versioning.ts b/packages/core/src/extensions/Versioning/Versioning.ts
@@ -247,7 +247,7 @@ export interface PreviewController<Output = any, Attributions = any> {
 export function sortSnapshotsNewestFirst(
   snapshots: VersionSnapshot[],
 ): VersionSnapshot[] {
-  return [...snapshots].sort((a, b) => b.createdAt - a.createdAt);
+  return snapshots.toSorted((a, b) => b.createdAt - a.createdAt);
 }
 
 /**

diff --git a/packages/core/src/extensions/tiptap-extensions/Link/helpers/autolink.ts b/packages/core/src/extensions/tiptap-extensions/Link/helpers/autolink.ts
@@ -109,8 +109,7 @@ export function autolink(options: AutolinkOptions): Plugin {
             return;
           }
 
-          const lastWordBeforeSpace =
-            wordsBeforeWhitespace[wordsBeforeWhitespace.length - 1];
+          const lastWordBeforeSpace = wordsBeforeWhitespace.at(-1) ?? "";
           const lastWordAndBlockOffset =
             textBlock.pos +
             textBeforeWhitespace.lastIndexOf(lastWordBeforeSpace);

diff --git a/packages/core/src/extensions/tiptap-extensions/Link/helpers/linkDetector.ts b/packages/core/src/extensions/tiptap-extensions/Link/helpers/linkDetector.ts
@@ -137,7 +137,7 @@ function countChar(str: string, ch: string): number {
  */
 function extractTld(hostname: string): string {
   const parts = hostname.split(".");
-  return parts[parts.length - 1].toLowerCase();
+  return (parts.at(-1) ?? "").toLowerCase();
 }
 
 function isValidTld(hostname: string): boolean {

diff --git a/packages/core/src/extensions/tiptap-extensions/UniqueID/UniqueID.ts b/packages/core/src/extensions/tiptap-extensions/UniqueID/UniqueID.ts
@@ -25,9 +25,7 @@ function removeDuplicates(array: any, by = JSON.stringify) {
   const seen: any = {};
   return array.filter((item: any) => {
     const key = by(item);
-    return Object.prototype.hasOwnProperty.call(seen, key)
-      ? false
-      : (seen[key] = true);
+    return Object.hasOwn(seen, key) ? false : (seen[key] = true);
   });
 }
 

diff --git a/packages/core/src/util/string.ts b/packages/core/src/util/string.ts
@@ -6,12 +6,12 @@ export function filenameFromURL(url: string): string {
   const parts = url.split("/");
   if (
     !parts.length || // invalid?
-    parts[parts.length - 1] === "" // for example, URL ends in a directory-like trailing slash
+    parts.at(-1) === "" // for example, URL ends in a directory-like trailing slash
   ) {
     // in this case just return the original url
     return url;
   }
-  return parts[parts.length - 1];
+  return parts.at(-1) ?? url;
 }
 
 export function isVideoUrl(url: string) {

diff --git a/packages/core/src/y/extensions/YCursorPlugin.ts b/packages/core/src/y/extensions/YCursorPlugin.ts
@@ -26,7 +26,7 @@ function isDarkColor(bgColor: string): boolean {
     if (col <= 0.03928) {
       return col / 12.92;
     }
-    return Math.pow((col + 0.055) / 1.055, 2.4);
+    return ((col + 0.055) / 1.055) ** 2.4;
   });
   const L = 0.2126 * c[0] + 0.7152 * c[1] + 0.0722 * c[2];
   return L <= 0.179;

diff --git a/packages/core/src/yjs/extensions/YCursorPlugin.ts b/packages/core/src/yjs/extensions/YCursorPlugin.ts
@@ -26,7 +26,7 @@ function isDarkColor(bgColor: string): boolean {
     if (col <= 0.03928) {
       return col / 12.92;
     }
-    return Math.pow((col + 0.055) / 1.055, 2.4);
+    return ((col + 0.055) / 1.055) ** 2.4;
   });
   const L = 0.2126 * c[0] + 0.7152 * c[1] + 0.0722 * c[2];
   return L <= 0.179;

diff --git a/packages/react/src/components/Comments/ThreadsSidebar.tsx b/packages/react/src/components/Comments/ThreadsSidebar.tsx
@@ -98,8 +98,8 @@ function sortThreads(
     // sort by latest comment in thread first
     return threads.sort(
       (a, b) =>
-        b.comments[b.comments.length - 1].createdAt.getTime() -
-        a.comments[a.comments.length - 1].createdAt.getTime(),
+        (b.comments.at(-1)?.createdAt ?? b.createdAt).getTime() -
+        (a.comments.at(-1)?.createdAt ?? a.createdAt).getTime(),
     );
   }
 

diff --git a/packages/react/src/components/Versioning/CurrentSnapshot.tsx b/packages/react/src/components/Versioning/CurrentSnapshot.tsx
@@ -64,7 +64,7 @@ export const CurrentSnapshot = ({
   // "Compare since beginning" diffs the live document against the oldest
   // snapshot. Shown only when current-version diffing is supported and there's
   // at least one snapshot to compare against.
-  const oldestSnapshot = snapshots[snapshots.length - 1];
+  const oldestSnapshot = snapshots.at(-1);
   const actions =
     comparisonEnabled &&
     canPreviewCurrent &&

diff --git a/packages/react/src/hooks/useStore.ts b/packages/react/src/hooks/useStore.ts
@@ -80,13 +80,11 @@ export function shallow<T>(objA: T, objB: T): boolean {
 
   return keysA.every(
     (key) =>
-      Object.prototype.hasOwnProperty.call(objB, key) &&
+      Object.hasOwn(objB, key) &&
       Object.is(objA[key as keyof T], objB[key as keyof T]),
   );
 }
 
 function getOwnKeys<T extends object>(obj: T): Array<string | symbol> {
-  return (Object.keys(obj) as Array<string | symbol>).concat(
-    Object.getOwnPropertySymbols(obj),
-  );
+  return [...Object.keys(obj), ...Object.getOwnPropertySymbols(obj)];
 }