Node.js – How to pass a value to another file

November 3, 2022

I have a project in which I use Express.js and activedirectory package for LDAP authentication.

I have a file called ad.js which includes-

exports.authUser = (username, password) => {
    ad.authenticate(username, password, function (err, auth) {
        if (err) {
            console.log('ERROR: ' + JSON.stringify(err));
            return;
        }
        if (auth) {
            console.log('Authenticated!');
        } else {
            console.log('Authentication failed!');
        }
    })
}

I call authUser in app.js-

app.post("/login", (req, res) => {
  let username = req.body.username;
  let password = req.body.password;
  authUser(username, password);
})

The authentication works but I want to access the value of auth in app.js.
What is the correct way to perform that?

Thanks for any advice.

>Solution :

You can "promisify" your function and then await for the result. The main function returns a promise object and the route awaits for that promise to resolve.

exports.authUser = (username, password) => {
    return new Promise((resolve, reject) => {
        ad.authenticate(username, password, (err, auth) => {
            if (err) {
                console.log(`ERROR: ${JSON.stringify(err)}`);
                return reject(err);
            }
            console.log(auth ? 'Authenticated!' : 'Authentication failed!');
            return resolve(auth);
        });
    });
};

app.post("/login", async (req, res) => {
    const username = req.body.username;
    const password = req.body.password;
    try {
        const auth = await authUser(username, password);
    } catch (error) {
        // do something
    }
});