get-class.js : [[Class]] を返す (ECMAScript5準拠)

get-class.js

/**
 * get-class.js
 *
 * @version 1.0.4
 * @author think49
 * @url https://gist.github.com/862098
 */

function getClass (arg) {
  var _class;

  if (arg === null) { // Null Type
    return null;
  }

  switch (typeof arg) {
    case 'undefined': // Undefined Type
    case 'boolean':   // Boolean Type
    case 'number':    // Number Type
    case 'string':    // String Type
      _class = null;
      break;
    default:          // Object Type
      _class = Object.prototype.toString.call(arg).slice(8, -1);
      break;
  }

  return _class;
}