Sheetjs: Excel: Found a problem with some content in file

[josh-hemphill]

I haven't been able to find a good way to debug this error. The file seems to be malformed, but I can't find anything wrong with the data being input.
I'm using the following function to abstract it.

function excel (data, options= {excel:{WorkBook:{}}}) {
    const {excel} = options;
    const wb = utils.book_new();
    wb.Props = {Company: 'My Company', CreatedDate:Date.now(), ...excel.WorkBook.Props};
    wb.Custprops = excel.WorkBook.Custprops || {};
    wb.Workbook = excel.WorkBook.Workbook || {};

    for (const key in data) {
        const element = data[key];
        utils.book_append_sheet(wb,utils.json_to_sheet(element,element?.sheetOptions || {}),key);
    }

    const now = new Date().toLocaleString([],{hour12:false,dateStyle:'short',timeStyle:'medium'}).replace(', ','_').replace(/[/ :]/g,'-');
    writeFile(wb,excel.fileName || `${excel.title}_${now}.xlsx`,{bookType:'xlsx'});
}

And for testing I've just been calling it with excel({'My Sheet':[{'Column 1':'hello','Column 2': 'hello world'}]}) and still been getting the error.
Here's an example file if it helps:
undefined_11-30-20_10-32-26.xlsx

[SheetJSDev]

Google Drive seems to be messing with the file, can you upload it here? If you open the issue page in your web browser, you should be able to drag-and-drop the file into the text input

[SheetJSDev]

Thanks for updating the file! The issue is with

CreatedDate:Date.now()

Date.now() is a number. When we write the properties, we don't check that the created date is a Date -- the value is directly written. The XML has something like

<dcterms:created>1606750346235</dcterms:created>

If you want to mark the created date when you do the write, pass a date object. You can either use new Date() or new Date(Date.now()) to create the object.

fiddle: https://jsfiddle.net/jot943mz/