Hello, I actually ran across this randomly while answering a question on stackoverflow, but either way

The current the typescript definition for ExcelCell is incorrect

(and retro-actively where it's used)

Current definition:

interface ExcelCell {
    value: ExcelCell;
    style: ExcelStyle;
}

This obviously makes no sense and would require you to recursively declare the ExcelCell inside the value property.

Supposed to be

interface ExcelCell {
    value: ExcelCellValue;
    style: ExcelStyle;
}