How to combine column using excel4node with for loop

Question

I'm trying using excel4node to covert my data to excel.

here is data :

[ 'AA', 'BB', 'CC' , 'DD'...]

I want each string is in 2 column in 1 row like this:

and now i'm stacking in the first row, i don't know how to combine the column.

here is what i trying to do is using forEach to iterate the data:

data.forEach((title, index) => {
    sheet.cell(1, index + 1, 1, index + 2, true).string(title);
});

and it always shows like this:

seems it overwrite BB and i don't know how to avoid it.

According the terminal it shows :

"Invalid Range for: B1:C1. Some cells in this range are already included in another merged cell range: A1:B1."

and i also don't know how to write right code for 'count' column

please help me finish this excel column,