How to use SheetJS XLSX with Angular 4 Typescript in the browser

It took me a while to figure this out, so I’ll share my code here.

You will need the `file-saver` and `xlsx` npm packages.

There are two important parts:

1. Make sure you specify the `meta` section in systemjs or else it won’t load `XLSX.utils`

2. Use the correct `XLSX.write` parameters, otherwise you will get `nodebuffer is not supported by this browser`