Boolean.prototype.js

Boolean.prototype.toggle = function() {
    return !this.valueOf();
  }
  /**
   * @description Parses mixed type values into booleans.
   * @param  {Mixed}        value 
   * @param  {Boolean}      nullOnFailure = false
   * @return {Boolean}
   */
Boolean.prototype.toBoolean: function(obj) {
  if (typeof obj === 'undefined')
    return false;

  if (typeof obj === 'string')
    obj = obj.toLowerCase().trim();

  switch (obj) {
    case 'true':
    case 'yes':
    case '1':
    case 1:
    case true:
      return true;
    case 'false':
    case 'no':
    case '0':
    case false:
    case 0:
    case null:
      return false;
    default:
      return Boolean(obj);
  }
}