Function getWorksheet

getWorksheet(
workbook: Workbook,
identifier: string | number | RegExp,
): Worksheet | undefined
Retrieves a worksheet by index, name, or RegExp pattern.
Parameters
- workbook: Workbook
  The ExcelJS workbook instance.
- identifier: string | number | RegExp
  The worksheet identifier.
Returns Worksheet | undefined
The matched worksheet or undefined.
Example
```
const sheet = getWorksheet(workbook, 'Sheet1');
const sheet = getWorksheet(workbook, 1);
const sheet = getWorksheet(workbook, /Sheet\d/);
```
- Defined in src/excel/excel.tsx:356