Question

i was seeking for a solution like this in stackoverflow and in google but this is
the idea

   a = {
  b: (conditionB? 5 : undefined),
  c: (conditionC? 5 : undefined),
  d: (conditionD? 5 : undefined),
  e: (conditionE? 5 : undefined),
  f: (conditionF? 5 : undefined),
  g: (conditionG? 5 : undefined),
 };

but i dont understand this… it doesnt work in nodejs i want to create an
object a with many objects inside but if that objects are in the form send
by the client

Answer 1

This can be achieved in 2 ways.

Either you use an if sentence for each conditional property as such:

    var a = {};
    if(conditionb){
      a.b = 5;
    }

Or if you don’t want to create an if sentence for every property then you assign properties using the notation you presented in the question and then remove unnecessary ones in a loop:

    a = {
      b: (conditionB? 5 : undefined),
      c: (conditionC? 5 : undefined),
      d: (conditionD? 5 : undefined),
      e: (conditionE? 5 : undefined),
      f: (conditionF? 5 : undefined),
      g: (conditionG? 5 : undefined),
    };
    for(var i in a){
      if(a[i] === undefined){
        delete a[i];
      }
    }