Configurable middleware in Express.js

app.js

// ...

databaseMiddleware = require("./middleware.js");

// ...

app.use(databaseMiddleware("/path/to/database/file.sqlite"));

// ...

middleware.js

module.exports = function databaseMiddleware(path) {
	database = sqlite.open(path);
	
	return function(req, res, next) {
		req.database = database;
		next();
	}
}