How to catch response in React js sent from NodeJs to check if email already exists in the database

Question

I had written a code to send a response if an email address already exists or a new user has been added. but don't know how to display it in front-end Reactjs.

var updateLimitQuery = `INSERT INTO default_users (userEmail, Role, monthlyGeneral, inflightGeneral, monthlySource, inflightSource) VALUES ("${userEmail}","Default","${tempMG}","${tempIG}","${tempMS}","${tempIS}")`;
        connection.query(updateLimitQuery, function(err, result){
            if(err)
            {
                if(err.code == 'ER_DUP_ENTRY' || err.errno == 1062)
                {
                    results = "Entry already exists"
                    res.send('Entry already exists');
                    console.log(results)
                }
                else{
                    results = "Other error in query"
                    res.send('SQL query error');
                    console.log(results)
                }
            }
            else{
                    results = "New user added"
                    res.send('New User added');
                    console.log(results)
                }

I want to pick that response in react js either after submit or before submit

Can somebody provide a code for Reactjs to display the response from node js as an alert box or in a variable?

Answer 1

You would use fetch. Example:

fetch("LINK_TO_API")
.then(res => res.json())        //convert response to json format
.then(res => console.log(res))  // console log response
);