[husainalshehhi]

Well, indirection can be quite helpful even for simple checks:

  if is_json(somestring) {
      // do something
  }

  function is_json(string s) {
      return JsonLib.convert(s) != NULL
  }

this indirection is easier to read rather than thinking too much about what JsonLib.convert(s) != NULL mean. This does not hinder debugging because you only debug this is_json function when the code does not evaluate is_json as expected. Every other time, you debug what's in the if statement.

The given example x.startswith("foo") is simple enough to include it directly. However, if there is a business reason for why "foo" is checked here, it will be difficult to understand why the check is there. This will be more difficult to read a code like this:

  if x.startwith("-")
      do something

instead of

  if is_yaml_node(x)
      do something

  def is_yaml_node(x)
      x.startwith("-")