node.js:Can't set headers after they are sent

Question

I am learning Node.js at the moment, and i am trying to create a shopping list application, and i am trying to implement a search route, which checks if the query matches the val, here is the code

const express = require('express');

const bodyParser = require('body-parser');



const app = express();

const port = 3000;



//Array List 

let list = ['Fish', 'Lettuce', 'Chicken'];



//Set view engine to pug

app.set('view engine', 'pug');

//use bodyParser





app.get('/', function(request, response){

    response.render('list', {list});

});



app.get('/search', function(request, response){

   return list.map(function(val){

      if(request.query.search === val){

          return response.send('Yup you got ' + val);

        }

     response.send('Not found')

    });

});



app.get('/new-item', function(request, response){

    response.render('new');

});



app.post('/add-item', function(request, response){

   let add = response.send(request.body);

   list.push(add);

});



app.listen(port, function(){

    console.log('Listening on Port 3000');

});

Now the problem is with the

/search

route's

if

conditional, i know the reason i am getting the error is because i can't use the

response.send

twice, i am looking for a way to send either response, based on if the condition is met.
Any help is appreciated
Thanks

Recommended for you: Get network issues from WhatsUp Gold. Not end users.

Answer 1

Move response.send('Not found') outside of the loop. Also, you shouldn't use Array.map here, use Array#find instead:

app.get('/search', function(request, response) {
   let foundVal = list.find(function(val) {
     if (request.query.search === val) {
       return val;
     }
   });
   if (foundVal) {
     return response.send('Yup you got: ' + foundVal);
   }
   response.send('Not found');
});

node.js:Can't set headers after they are sent

Sign up