bit masking fun with javascript.

JSStateWithBitFlags.js

/**
 * A map of bit masks that correlate to a person's status.
 * @type {Object}
 */
var personStatus=(function(){
  var i=0.5;
  return {
    CODING:(i*=2),
    EATING:(i*=2),
    READING:(i*=2),
    SLEEPING:(i*=2),
    WORKING:(i*=2)
  };
})();

/**
 * A State object that uses bit flags to maintain state.
 * @constructor
 */
function State(){
  this._state=0;
}
/**
 * @param {number}
 */ 
State.prototype.is=function(number){
  if(number < 1){
    return false;
  }
  return !!(this._state&number);
};
State.prototype.set=function(number){
  this._state=this._state|number;
};

var joeState=new State;
joeState.is(personStatus.CODING);//false
joeState.set(personStatus.CODING);
joeState.is(personStatus.CODING);//true