Await promise - NodeJs

user_4166130 0
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I'm trying to assign a value to the variable myleadId depending on leadId.length. The goal is that myleadId will have a value after this step to continue with the next step. The problem is that myleadId is undefined when leadId.length <= 0 (else condition).

app.post('/sendMessage2agent', async (req, res) => {
  getEnterpriseIDbyContact(req.body.recipient, knex).then((enterpriseId) => {
    getLeadIDbyContact(req.body.sender, knex).then((leadId) => {
      var myleadId;
      if (leadId.length > 0) {                  
        myleadId = leadId;  //works great!
      } else {
        getChannelIdByName(req.body.channel, knex).then((channelId) => {        
          return createLeadOnEnterprise(req.body.sender, enterpriseId, channelId, knex).then((newleadId) => {       
            console.log('newleadId: ' + newleadId); //newleadId is 5
            myleadId = [{'id': newleadId}]; //doesn't work :(
            return;
          });                               
        });                 
      }                         
    
      console.log('myleadId: ' + JSON.stringify(myleadId)); // myleadId is undefined when leadId.length>0 is false. I expect myleadId=[{'id': 5}]
    });     

    res.json(req.body);
  });
});
node.js undefined
1 Answers

The problem is that you're not awaiting your promises. That way they will finish at a different time than your console.log. What you should also see is that the message myleadId: ... appears before newleadId: ... in the console. This is because promises execute asynchronously. So they let other code continue while they are executing. To ensure that a promise is awaited before continuing with the main function you should use await. With that you can also remove the .then callbacks to improve readability.

app.post('/sendMessage2agent', async (req, res) => {
  const enterpriseId = await getEnterpriseIDbyContact(req.body.recipient, knex);
  const leadId = await getLeadIDbyContact(req.body.sender, knex);
  let myleadId;
  if (leadId.length > 0) {                   
    myleadId = leadId;
  } else {
    const channelId = await getChannelIdByName(req.body.channel, knex);
    const newleadId = await createLeadOnEnterprise(req.body.sender, enterpriseId, channelId, knex);  
    console.log('newleadId: ' + newleadId);
    myleadId = [{'id': newleadId}];
  }                           
  
  console.log('myleadId: ' + JSON.stringify(myleadId));
      
  res.json(req.body);
});
user_139001390
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