Technically, Web Worker is not a library, and Traceur is used to translate ES6 to ES5 while browser support catches on, so AngularJS is the only library used.

The non-Traceur ES5 version at https://github.com/audreyt/500lines/tree/master/spreadsheet/... has exactly the same line count, but with more idiomatic workarounds that's less clear to students new to web development (the audience of this book).

It is possible to replace AngularJS (the only external library) with regular blur/focus/change handler as @xem shows — without affecting the line counts — but the separation of concerns between view, logic and worker would be less clear.