How do you get a list of the names of all files present in a directory in Node.js?

You can use the fs.readdir or fs.readdirSync methods. fs is included in Node.js core, so there's no need to install anything.

fs.readdir

const testFolder = './tests/';
const fs = require('fs');

fs.readdir(testFolder, (err, files) => {
  files.forEach(file => {
    console.log(file);
  });
});

fs.readdirSync

const testFolder = './tests/';
const fs = require('fs');

fs.readdirSync(testFolder).forEach(file => {
  console.log(file);
});

The difference between the two methods, is that the first one is asynchronous, so you have to provide a callback function that will be executed when the read process ends.

The second is synchronous, it will return the file name array, but it will stop any further execution of your code until the read process ends.

IMO the most convenient way to do such tasks is to use a glob tool. Here's a glob package for node.js. Install with

npm install glob

Then use wild card to match filenames (example taken from package's website)

var glob = require("glob")

// options is optional
glob("**/*.js", options, function (er, files) {
  // files is an array of filenames.
  // If the `nonull` option is set, and nothing
  // was found, then files is ["**/*.js"]
  // er is an error object or null.
})

The answer above does not perform a recursive search into the directory though. Here's what I did for a recursive search (using node-walk: npm install walk)

var walk    = require('walk');
var files   = [];

// Walker options
var walker  = walk.walk('./test', { followLinks: false });

walker.on('file', function(root, stat, next) {
    // Add this file to the list of files
    files.push(root + '/' + stat.name);
    next();
});

walker.on('end', function() {
    console.log(files);
});