Excel

Donald Knuth says this could well be the most complex program ever; who am I to disagree.

Many people use Excel as cross between a Database, programming tool and general data validation tool. You often need to upload Excel spreadsheets into more complex systems or use a spreadsheet as the basis for something more complicated.

Reading Excel in C# and Javascript

• https://www.codeproject.com/Tips/801032/Csharp-How-To-Read-xlsx-Excel-File-With-Lines-Of-C
• https://stackoverflow.com/questions/8238407/how-to-parse-excel-file-in-javascript-html5
• https://github.com/SheetJS/js-xlsx