perf: replace Object assign with direct mutation in feature code (#5048)

Object.assign is very performance Heavy, when compared with direct assignment, and can easily be replaced with direct mutations in the creational functions. Since theese get called *a lot* when the data changes, especially with large amounts of data, the performance impact is quite huge.

Co-authored-by: Günter Manz <[email protected]>

packages/table-core/src/core/cell.ts

@@ -52,14 +52,11 @@ export function createCell<TData extends RowData, TValue>(
   }
 
   table._features.forEach(feature => {
-    Object.assign(
-      cell,
-      feature.createCell?.(
-        cell as Cell<TData, TValue>,
-        column,
-        row as Row<TData>,
-        table
-      )
+    feature.createCell?.(
+      cell as Cell<TData, TValue>,
+      column,
+      row as Row<TData>,
+      table
     )
   }, {})
 

packages/table-core/src/core/column.ts

@@ -119,9 +119,9 @@ export function createColumn<TData extends RowData, TValue>(
     ),
   }
 
-  column = table._features.reduce((obj, feature) => {
-    return Object.assign(obj, feature.createColumn?.(column, table))
-  }, column)
+  for (const feature of table._features) {
+    feature.createColumn?.(column, table)
+  }
 
   // Yes, we have to convert table to uknown, because we know more than the compiler here.
   return column as Column<TData, TValue>