Another one impletementation of "maybe" monad in JavaScript

maybe-example.js

var o = { data: { success: true } }

maybe('o')
    .with('data')
    .with('success')
    .if(function(x){     
	return x === true; 
    })
    .do(function(x){ 
	if(x === null){return "if failed"} else{ return "if succeded"} 
    })
    .val()
    
maybe('o')
    .with('no')
    .with('data')
    .val()    

maybe.js

var maybe = (function(){
    function maybe(o){
		if(typeof this[o] !== "undefined" && this[o] !== null){
			return result(this[o]);
		} else {
			return result(null);
		}
	};
	
	function withFunc(obj, prop){
		if(obj && typeof obj[prop] !== "undefined" && obj[prop] !== null){
			return result(obj[prop]);
		} else {
			return result(null);		
		}
	}
	
	function result(obj){
		return {
			with: function(prop){
				return withFunc(obj,prop);
			},
			
			val: function(defaultValue){
				if(typeof obj !== "undefined" || obj !== null) {
					return obj;
				}
				if(typeof defaultValue !== "undefined") return defaultValue;
				return null;				
			}, 
			
			if: function(condition){
				if(condition(obj)){
					return result(obj);
				}
				return result(null);
			},
			
			do: function(action){
				if(typeof obj !== "undefined" || obj !== null) {
					return result(action(obj));
				}				
				return result(null);
			}
		}	
	}	

    return maybe
})()