This userscript presents a button on ShareLaTeX to download bibtex from a Mendeley group library and write a "cleaned" file on Dropbox in the same ShareLaTeX document folder. The code, which is geared towards astronomical research, checks the bibtex entries for compliance with journals such as AJ and ApJ, normalizes the bibtex entries, imposing a uniform cite key format that guarantees a unique cite key without having to resort to attached "a", "b", "c", etc suffixes. MenDBib generates 3 files on Dropbox: the viable bibtex file (called mendbib.bib) and a file (mendbib_prob.bib) that holds any nonviable bibtex entries (these are typically missing one or more required components of information, and/or have typos that need to be corrected). A third file, "mendbib_info.README" provides decription of the other 2 files and instructions for dealing with off-nominal cases. The code is heavily commented and could also serve as a tutorial for javascript/userscript/TamperMonkey beginners like me who benefit from seeing real-life applications.
