Ask HN: How would you build a Excel file uploader with inline preview?

I like the file uploader of Dataiku DSS[1] wich allows you to upload Excel/csv files and edit them in the previewer befor commoting them in the db. My question is this: is there any Js open-source library like that one with inline preview and editing of spreadsheets? If it doesn't exist, I would like to have an idea how I could build one with available tools.

[1]: https://www.dataiku.com/dss/editions/