Alternate title can be how to extract column names from a xlsx file. Because that is my goal.

I want to extract the column names from xlsx files, I have written code for that but the problem is for larger files having > 10k records, It is taking a lot of time and even my page hangs and is unresponsive.

extractColumnsXlsx(file: File): Promise<string[]> {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();

    reader.readAsArrayBuffer(file);

    reader.onload = (event) => {
      const arrayBuffer = event.target?.result;

      try {
        const workbook = XLSX.read(arrayBuffer, { type: 'array' });
        const firstSheetName = workbook.SheetNames[0];
        console.log("First Sheet Name:", firstSheetName);

        const worksheet = workbook.Sheets[firstSheetName];
        console.log("Worksheet:", worksheet);

        console.log("!ref Property ->", worksheet['!ref']);

        let columnNames: string[] = [];

        if (worksheet['!ref']) {
          const parts = worksheet['!ref'].split(':');
          console.log("First and Last Cells: ", parts);

          const refObj = XLSX.utils.decode_range(worksheet['!ref']);
          const firstColIndex = refObj.s.c;
          const lastColIndex = refObj.e.c;

          console.log("firstColIndex:", firstColIndex);
          console.log("lastColIndex:", lastColIndex);

          let firstRowData;
          try {
            firstRowData = XLSX.utils.sheet_to_json(worksheet, {
              header: 1,
              range: `${XLSX.utils.encode_cell({ c: firstColIndex, r: 0 })}:${XLSX.utils.encode_cell({ c: lastColIndex, r: 0 })}`,
            });
          } catch (error) {
            console.error('Error reading first row: ', error);
          }

          if (firstRowData && firstRowData.length) {
            columnNames = firstRowData[0]; // Assuming first row contains column names (index 0)
          } else {
            console.warn('Failed to read column names from first row.');
          }

          console.log('Column Names:', columnNames);
          resolve(columnNames);
        } else {
          console.error('Missing of invalid !ref property in worksheet!');
          reject(new Error('Missing !ref property in worksheet'));
        }
      } catch (error) {
        reject(error);
      }
    };

    reader.onerror = (error) => reject(error);
  });
}

I was searching for some method to only read the first row from the xlsx file but couldn’t find anything useful. Some one suggested using something like this

 const workbook = xlsx.readFile('path/to/your/file.xlsx', { sheetRows: 5 });

but I don’t have the file path, I am taking file as an input from user using the input tag.