socket io nodejs use variable from one socket listener to another socket listener?

Question

var x ="apple";

socket.on('fruits',function(data){
  var x = data;  //var x is orange here
});

console.log(x); /// but var x is still apple here.....


socket.on('DatatoServer',function(  
   socket.in(x).emit('receivedData', data); ///I want this x to be orange
});

how do I make that var x to become global variable?

or is there a way I can use that orange var x in my second socket.on listener above?

Any help is appreciated

Possible duplicate of [What is the scope of variables in JavaScript?](https://stackoverflow.com/questions/500431/what-is-the-scope-of-variables-in-javascript) — Jacob Thomas, May 09 '19 at 19:54

jdavison · Answer 1 · 2019-05-09T20:13:47.827

0

When you use the var keyword you are actually declaring a new variable x within the scope of your callback.

To reference x in the global scope, remove the var and set it directly.

Also, the fact that it's a callback might change the global scope, using an arrow function for your callback could resolve this.

socket.on('fruits', (data) => { 
    x = data; //var x is orange here
 });

edited May 09 '19 at 20:13

answered May 09 '19 at 19:57

jdavison

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1
9

I tried removing var, so it becomes x ="apple"; also tried x ="data"; still getting apple – Tosps May 09 '19 at 20:04
You would need To remove the other var, inside the callback – jdavison May 09 '19 at 20:08
my third line of code, I tried x = "data" , still getting apple for 5th and 7th line of code – Tosps May 09 '19 at 20:12
See my edits, and review the scoping rules in the linked answer – jdavison May 09 '19 at 20:14

socket io nodejs use variable from one socket listener to another socket listener?

1 Answers1