How to set up an IF condition within mysql package in node.js

I'm using mysql package for node.js Studying the documentation did not help me with my question. I want to make following:

if (SELECT table_field WHERE id = some_value ){
  // execute some code
} else{
  // execute some code
}

So I want SELECT to return either TRUE or FALSE (like EXISTS operator) How can I do so with node.js ?