External links not preserved when writing out xlsx #2306
Description
I have an .xlsx file that contains a formula that references an external workbook, for example :
='[externalwb.xlsx]Sheet1'!$A$1
When Excel created the .xlsx file, formula is actually stored as :
='[1]Sheet1'!$A$1
The reference to externalwb.xlsx is stored in the embedded file "xl/externalLinks/_rels/externalLink1.xml.rels".
When I parsed the .xlsx file setting the bookDeps and bookFiles options to true, and then wrote the workbook object to a new .xlsx file, that file couldn't be opened in excel properly because it didn't contain the external link information.
During write, SheetJS should include the xl/externalLinks information.