phpjs/functions/var/is_scalar.js

php.js offers community built php functions in javascript

function is_scalar(mixed_var) {
  // From: http://phpjs.org/functions
  // +   original by: Paulo Freitas
  // *     example 1: is_scalar(186.31);
  // *     returns 1: true
  // *     example 2: is_scalar({0: 'Kevin van Zonneveld'});
  // *     returns 2: false
  return (/boolean|number|string/).test(typeof mixed_var);
}