throwing an error if i pass 'null' or 'undefined' value for column span.

[muraliaswilco]

I was checking export data to excel format in this webiste https://catamphetamine.gitlab.io/write-excel-file/

Column span. Even if a cell spans N columns, it should still be represented as N individual cells in the data. In that case, all the cells except the left-most one will be ignored. One could use null or undefined to represent such ignored cells. For example, if the first cell in a row spans 3 columns, then the row would look like [{ value: 'Text', span: 3 }, null, null, { value: 'After text' }].

based on the above documentation i gave 'null' and 'undefined' value for column span but it's throwing an error in the console (i.e. Cannot read properties of null (reading 'value')). i have give data in the following format