xlsx.js

There was a funny Microsoft license for Xlsx.js (a lib that read Excel files in browser): It was allowed to distribute freely… as long as it runs on Windows: > (F) Platform Limitation- The licenses granted in sections 2(A) & 2(B) extend only to the software or derivative works that (1) are run on a Microsoft Windows operating system product, and (2) are not Excluded Products. So you could not deliver it on Safari, but also not on Chrome if it ran on Mac. Aaaand that is why the JSXLSX implementation was developed, exactly the same as xlsx.js but without the restriction. https://github.com/stephen-hardy/xlsx.js/issues/8

SheetJS was created because of a Microsoft licensing issue with a library (https://github.com/stephen-hardy/xlsx.js/issues/8). The other project had a nonstandard license with a clause that only applied to browsers run on Microsoft Windows, which is really bizarre for a JS library that can run on any browser. Apparently the original developer was working for Microsoft at the time, and Microsoft mandated the license clause. In a funny twist of fate, Microsoft now uses SheetJS open source to power some Excel exports in Office 365! https://tasks.office.com/License.html is the license disclosure, and you can actually see it in action in the exported files. We were blown away when we found out. It's the ultimate endorsement! Oftentimes we just wonder what would have happened if Microsoft just let the original project adopt a standard open

> you'll be in violation if you run it on a Thursday Indeed, there is a JS library opensourced by Microsoft to decode Excel files, named xlsx.js. In the license, it is written... that it cannot run on another OS than Windows. It means even though it's Javascript, the page hosting it cannot be viewed on a Mac or Linux. Long story short, Stuart Knightley created a clean room implementation named js-xlsx to do the same thing, without the lawyer string attached. https://github.com/stephen-hardy/xlsx.js/issues/8

I looked at that project but it uses a really strange non-free license that should be avoided. https://github.com/stephen-hardy/xlsx.js/issues/8

There's a really nice XLSX reader and writer by Stephen Hardy, a Microsoft developer: https://github.com/stephen-hardy/xlsx.js/ blog post: http://blog.innovatejs.com/?p=24

It's better to be safe than sorry, as the saying goes. I've never been burned personally. I'm also pretty sure that anyone working for a large software company is warned about using third party code or snippets found on expertsexchange or stackoverflow or random blogs. Normally people are well intentioned, but sometimes you stumble upon repos with very strange licenses (for example, a javascript repo that has operating system restrictions https://github.com/stephen-hardy/xlsx.js/issues/8 ). It's usually not of a concern for most people working on small projects (after all, another party has to notice and then decide to take action), but if you are trying to enter an industry with a highly litigious incumbent then you should make sure your ducks are in a row first.

"It would be a good idea if github enforced some convention to make sure the free repo's they provide for open source really are licensed under an OSI approved license." I wholeheartedly agree. Every once in a while you stumble upon a landmine: https://github.com/stephen-hardy/xlsx.js/issues/8