Express send response and catch it in client

Question

im trying to have the user send some data to the server, where it gets saved into a db, after this I would like to send a message back to the user (for example containing the id of the newly added object), but I was not yet able to succeed my code:

    router.post('/sendSnippet', function (req, res) {
    req.on('data', function(data) {
        User.findOne({email: req.user.email}).then((userToEdit) =>{
            if(userToEdit){
                var newSnippet = {
                    "types":[],
                    "code": data.toString()
                }
                userToEdit.snippets.push(newSnippet)
                userToEdit.save().then(()=>{
                    res.redirect('/profile/');
                    ----send response here----
               })
            }
        })
    })
});

and this is the client side function that sends the new data, im also guessing there is a better way to do this, but this worked so far (however any feedback would be appreciated!)

function sendSnippet(){
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.open('POST', '/profile/sendSnippet', true);
    xmlHttp.send(data to send);
}

thanks for any help in advance!

Answer 1

You can do it like this using async/await:

   router.post('/sendSnippet', async (req, res) => {

    const userToEdit = await User.findOne({email: req.user.email});
    if (userToEdit) {
       var newSnippet = {
                    "types":[],
                    "code": data.toString()
    }
     userToEdit.snippets.push(newSnippet);
     const results = await userToEdit.save();
     res.send({results: results._id});// it will send response
});

At the client side you can do this:

function sendSnippet(){
    var xmlHttp = new XMLHttpRequest();

    xmlHttp.onreadystatechange = function() {
    if (xmlHttp.readyState === 4) {
      console.log(xmlHttp.response);
    }
  }

    xmlHttp.open('POST', '/profile/sendSnippet', true);
    xmlHttp.send(data to send);
}

Check here for more details.