SheetJS – Parse And Manipulate Excel Spreadsheets In The Browser

SheetJS (source code available on GitHub) is an extremely useful JavaScript library that enables you to have Microsoft Excel spreadsheets parsed directly in the browser without any backend interaction necessary.

What makes SheetJS even more impressive is the ability to query spreadsheets in-place with an SQLite-compatible SQL language called WebSQL. Check out the example on the website to see how awesome this is.

Together with a grid component such as Handsontable (source code) SheetJS allows for on-the-fly display, querying and manipulation of Excel spreadsheets.

For a more complex real life use case see this blog post by Patrick McKenzie: Design and Implementation of CSV/Excel Upload for SaaS