function props(str) {
  return str
    .replace(/\.\w+|\w+ *\(|"[^"]*"|'[^']*'|\/([^/]+)\//g, '')
    .replace(globals, '')
    .match(/[$a-zA-Z_]\w*/g)
    || [];
}
Return immediate identifiers in `str`.

@param {String} str
@return {Array}
@api private