Although I'm still working core excel API (https://github.com/securedeveloper/javascript-excel) but I took some time to find the issues, tracked down the reasons and fixed them.
- tempa-xlsx (instead of github) to avoid any installation issue.
- add
xlsxin dev dependency to avoid dependency collision. - Merged PRs addressing cell width and cell data type (int)
** Followup
After (https://github.com/securedeveloper/javascript-excel) I will change library to use Typescript, hence typings will be provided along the way.