What is the current directory used by fs module functions?
It's the directory where the node interpreter was started from (aka the current working directory), not the directory of script's folder location (thank you robertklep).
Also, current working directory can be obtained by:
process.cwd()For more information, you can check out: https://nodejs.org/api/fs.html
EDIT: Because you started app.js by node app.js at ExpressApp1 directory, every relative path will be relative to "ExpressApp1" folder, that's why fs.createWriteStream("abc") will create a write stream to write to a file in ExpressApp1/abc. If you want to write to ExpressApp1/routes/abc, you can change the code in members.js to:
fs.createWriteStream(path.join(__dirname, "abc"));For more:
https://nodejs.org/docs/latest/api/globals.html#globals_dirname
https://nodejs.org/docs/latest/api/path.html#path_path_join_paths