My rule of thumb is if you think the variable type may be useful to others reading your code, append it to the end. This is generally useful if you have the same data going through different forms.

Let's see if I can write something, that others understand with no context.

  //For this example let's ignore the nuances of names.
  function (nameUserinput) {
    if(isValidName(nameUserinput)) {
      return processName(nameUserinput))
    } else {
      return { first: '', middle: '', last: '' }
    }
  }

  function isValidName () {
    return (containsAtLeastOneSpace(nameUserinput) &&
            containsLessThanThreeSpaces(nameUserinput) &&
            hasThreeOrMoreCharacters(nameUserinput) &&
            noSpacesOnEnd(nameUserinput))
  }

  function processName (nameUserinput) {
    const nameObj = { middle: '' };
    const nameUserinputArray = nameUserinput.split(' ');
    if(nameUserinputArray.length = 2) {
      [nameObj.first, 
       nameObj.last] = nameUserinputArray;
    } else if(nameUserinputArray.length = 3) {
      [nameObj.first, 
       nameObj.middle, 
       nameObj.last] = nameUserinputArray;
    }
  }

nameObj and nameUserinput and nameUserinputArray are all the same data in different forms. I think it's helpful to start them with the same prefixes, but change the suffix with the type to communicate that.

You could imagine taking this a step further, with nameStatemachine. You might chart a person's course through life, do they go to law school, medical school, get married etc.

I've been meaning to write a blog post on this. But this does follow my most important words first rule. You'll see a lot of similarities there, just not on this exact topic.

https://soft-wa.re/naming-conventions/