SheetJS/js-xlsx — pull request #103 by christocracy (2014-08-27 05:41:02+00:00)
Title: Formulas are ignored when writing sheet. 

Implement fix as advised by @SheetJSDev
https://twitter.com/christocracy/status/504469597773643776

Ran tests: all passed https://www.dropbox.com/s/b1rw0jvgy8riwoj/Screenshot%202014-08-27%2001.33.25.png?dl=0