Add support for Excel (xls/xlsx) and Calc (ods) files

[krassowski]

jupyterlab-spreadsheet depends on xlsx which seems to be the most popular choice. Alternatives include exceljs and xlsx-populate. This needs further evaluation (contributions welcome!).

We would ideally want to have:

• typescript typings
• modern codebase (no jQuery please)
• both proprietary and open formats support
• as little peer dependencies as possible
• good maintainership history (especially with regard to security patches)
• high fidelity/standard compliance

Implementation wise, we would want to implement:

• multiple sheets support (but the initial proof-of-concept version could just use the first sheet)
• "save as" feature so that one can convert Excel sheets into more friendly csv/tsv format

Please feel free to comment to add your own needs and wishes!

[krassowski]

It looks that actually sheetjs might be the solution. Some quick notes from NPM:

• exceljs
  • size: 25.6 MB
  • lase release: 3 months ago
  • weekly downloads: 333,425
• xlsx-populate
  • size: 15.1 MB
  • lase release: a year ago
  • weekly downloads: 25,007
• sheetjs - xlsx
  • size: 8.94 MB
  • lase release: 18 days ago
  • weekly downloads: 1,099,476