I am trying to use map inside another map when creating a table for a word file using npm package docx.

The file is created, but when I try to open it in word it says that the file format is not supported. Everything works fine if I don't use the second map function so I know this is the problem.

This is what I have:

export const createTable = (items) => { 
    let loopTables = items.map((item1) => 
                   
                new Table({
                    columns: 5,
                    width: 0, 
                    columnWidths: [2100, 1100, 1100, 1100, 1900], 
                    layout: TableLayoutType.FIXED,
                    rows: [
                        new TableRow({
                            children: [
                                new TableCell({
                                    children: [new Paragraph({
                                        children: [
                                            new TextRun({
                                                text: `Main item ${item1[0].Group1}`,
                                            }),
                                        ]
                                    }),],
                                    columnSpan: 5,
                                }),
                            ],
                        }),
                        item1.map((item2) =>
                        new TableRow({
                            children: [
                                new TableCell({
                                    children: [new Paragraph({
                                        children: [
                                            new TextRun({
                                                text: `Nested item ${item2.Group2}`,
                                            }),
                                        ]
                                    }),],
                                    columnSpan: 5,
                                }),
                            ],
                        }),
                        )
                    ]
                }),
            )
            return loopTables
}

loopTables is then inserted in another file like this:

{
                properties: {
                    type: SectionType.CONTINUOUS,
                },
                children: createTable(items) //Here we call the function that generates the table. It works fine without the nested map function.
            },

Any idea whats wrong and what I should do to fix it?