Node.JS - use writeFile or fileStream for large file

I creat a shp-file on the node server (as a buffer for my concern), and its size can be 5-70 Mb afterwards I want to save it on the server.

I wander whats the best way to save it, fs.writeFile or fs.createWriteStream. thank you all.

the server is node express , forgot to mention. code example will be great!