Utility function for checking if a value is truthy

_exists.md

function _exists (thing) {
  const IS_UNDEFINED = 'undefined' === (typeof thing)
  const IS_NULL      = null === thing
  if (IS_UNDEFINED || IS_NULL) return false

  const TYPE = (typeof thing)
  const IS_OBJECT = ('object' === TYPE)
  const IS_STRING = ('string' === TYPE)
  const IS_NUMBER = ('number' === TYPE)
  const IS_ARRAY  = (Array.isArray(thing))

  if (IS_STRING || IS_ARRAY) return 0 < thing.length
  if (IS_NUMBER) return 0 < String(thing).length
  if (IS_OBJECT) return 0 < Object.keys(thing).length

  return true
}