switch-state-ish.js

var Switch = function(expr){
        return new YetSucceed(expr);
}

var Succeed = { case : function(cond,proc){  return this; } };

var YetSucceed = function(expr){};
YetSucceed.prototype.case = function(cond, proc){
    if(cond){
        proc();
        return Succeed;
    }
    return this;
}
 
var x = 0;
 
new Switch(true).
        case(x > 0, function(){
              console.log(x + " is positive.");
        }).
        case(x === 0, function(){
                console.log(x + " is zero. ");
        }).
        case(x < 0, function(){
                console.log(x + " is negative . ");
        });