async/await inexpressive not able to return properly

Question

async/await inexpressive not able to return properly

Currently, I am working on a project involving an express app and incorporating async/await in my routes. However, I've encountered an issue where it seems to be skipping the wait for the findOneUser call to complete before moving on to the next line:

app.post ('/api/authenticate', async(req, res) => {
  console.log('GET TO AUTHENTICATE')
  const { email, password } = req.body;
  const user_db = await users.findOneUser( email );
  console.log("user_db", user_db)
  return user_db
});

 const findOneUser = (email) => {
    console.log("email", email)
     pool.query('SELECT * FROM users where email = $1', [email], (error, results) => {
      if (error) {
        throw error
      }
      console.log("RESULT", results.rows)
       results.rows
    })
  }

In the terminal logs below, you can observe that the user_db_log appears before the RESULT log. According to my understanding of async/await, the user_db code should have waited for the execution of the user.findOneUser method:

GET TO AUTHENTICATE

email

<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="3d58455c504d51587d52484951525256135e5250">[email protected]</a>

user_db undefined

RESULT 

[
  {
    id: 11,
    first_name: 'Test',
    last_name: 'User',
    email: '<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="01756472757472647341756472752f626e6c">[email protected]</a>'
  }
]

javascript express async-await

Answer 1

Answer №1

Here's a suggestion on how to approach this using Promise and async/await

 app.post ('/api/authenticate', async(req, res) => {
      console.log('GET TO AUTHENTICATE')
      const { email, password } = req.body;
      const user_db = await users.findOneUser(email);
      console.log("user_db", user_db)
      return user_db;
    });


 const findOneUser = async (email) => {
        var myProm = () => {
            return new Promise((resolve, reject) => {
                pool.query('SELECT * FROM users where email = $1', [email], (error, results)=> {
                    error ? reject(error) : resolve(results);
                });
            });
        }
        var result = await myProm();
        return result;
  }

Answer 2

Here's a suggestion on how to approach this using Promise and async/await

 app.post ('/api/authenticate', async(req, res) => {
      console.log('GET TO AUTHENTICATE')
      const { email, password } = req.body;
      const user_db = await users.findOneUser(email);
      console.log("user_db", user_db)
      return user_db;
    });


 const findOneUser = async (email) => {
        var myProm = () => {
            return new Promise((resolve, reject) => {
                pool.query('SELECT * FROM users where email = $1', [email], (error, results)=> {
                    error ? reject(error) : resolve(results);
                });
            });
        }
        var result = await myProm();
        return result;
  }

Answer 3

Answer №2

Waiting for Awaits: Understanding how await functions wait for promise resolution.

When it comes to your findOneUser function, the problem lies in the fact that it does not return a promise, causing await to execute immediately and return.

To fix this issue, either add async functionality to your findOneUser function (which wraps the response in a promise) or create a new promise within the function and wrap the response before returning it.

Answer 4

Waiting for Awaits: Understanding how await functions wait for promise resolution.

When it comes to your findOneUser function, the problem lies in the fact that it does not return a promise, causing await to execute immediately and return.

To fix this issue, either add async functionality to your findOneUser function (which wraps the response in a promise) or create a new promise within the function and wrap the response before returning it.

async/await inexpressive not able to return properly

Answer №1

Answer №2

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