Passing a variable from ReactJS frontend to NodeJS back end using a GET route

Question

I am working on a react app and am trying to find a way to pass a variable I define in my front-end (Question.js) to my back-end (server.js) so that I can issue different queries. I have the code

//Question.js

state = {
        data: null
    };

    componentDidMount() {
        this.callBackendAPI()
            .then(res => this.setState({ data: res.express }))
            .catch(err => console.log(err));
    }

    callBackendAPI = async () => {
        const response = await fetch('/express_backend');
        const body = await response.json();

        if (response.status !== 200) {
            throw Error(body.message)
        }
        return body;
    };

//server.js

con.connect(function (err) {
    if (err) throw err;
    con.query("SELECT question FROM s1questions WHERE ID = 1", function (err, result, fields) {
        if (err) throw err;
        app.get('/express_backend', (req, res) => {
            var x = JSON.stringify(result[0].question);
            res.send({ express: `${x}` });
        });
    });
});

Your route handler probably shouldn't be defined within your database connection callback Also, what is the database package that you're using? You'll want to use parameterized queries in order to retrieve your questions — dillon
– dillon, Commented Jan 21, 2020 at 3:22

dillon · Accepted Answer · 2020-01-21 03:26:48Z

1

Your sever should probably split your database connection from your route handler definitions. Also, you could use query parameters to access questions based on their id in the database.

// question.js
    callBackendAPI = async () => {
        const response = await fetch(`/express_backend?questionId=1`);
        const body = await response.json();

        if (response.status !== 200) {
            throw Error(body.message)
        }
        return body;
    };

// server.js
app.get('/express_backend', (req, res) => {
  const { questionId } = req.query;

  // query database for question by id
});

answered Jan 21, 2020 at 3:26

dillon

7336 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Arun Kamalanathan Over a year ago

@coldcav Please accept the answer if you find it helpful.

Collectives™ on Stack Overflow

Passing a variable from ReactJS frontend to NodeJS back end using a GET route

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related