One of my many attempts to create behavior like a maybe monad in javascript.

mabyInJavascript.js

var maybe = function(item) {
    var __internal = item;
    this.result = function(accessor, __default) {
        if (!__internal) {
            return new type(accessor).is_func() ? __default : accessor;
        }
        return new type(accessor).is_func() ? accessor(__internal) : __internal;
    };

    this.select = function(accessor) {
        if (!__internal) {
            return new maybe(null);
        }
        if (new type(accessor).is_string()) {
            return new maybe(__internal[accessor]);
        }
        else {
            return new maybe(accessor(__internal));
        }
    };

    function type(obj) {
        this.is = function(type) {
            return typeof obj === type;
        };
        this.is_object = function() {
            return typeof obj === "object";
        };
        this.is_func = function() {
            return typeof obj === "function";
        };
        this.is_string = function() {
            return typeof obj === "string";
        };
    }
};

/*Testing Starts Here*/
var test = {
    address: {
        city: null,
        homes: ["first", "second"]
    }
};

var mec = new maybe(test).select(function(c) {
    return c.address;
}).select(function(c) {
    return c.city;
}).result(function(c) {
    return c;
}, "__default");

console.log(mec);

var meh = new maybe(test).select("address").select("homes").result({
default:
    "yarrs"
});

console.log(meh[0]);

mabyMonad2.js

var test = {
    address: {
        city: 'crazy'
    }
};

var maybe = function (item) {
    var maybeProto = {
        __internal : item,
        result : function (accessor, __default) {
            if (!__internal) { 
                return typeof accessor === "string" ? accessor : __default;
            }
            if (typeof accessor === "string"){
                return __internal;
            }
            else { return accessor(__internal); }
        },

        select : function (accessor) {
            if (!__internal) { return new maybe(null); }
            if (typeof accessor === "string"){
                return new maybe(__internal[accessor]);
            }
            else { return new maybe(accessor(__internal)); }
        }
    };
    return maybeProto;
};

var mec = new maybe(test)
    .select(function (c) { return c.address; })
    .select(function (c) { return c.city; })
    .result(function (c) { return c; }, "__default");

alert(mec);
    
var meh = new maybe(test)
    .select("address")
    .select("city")
    .result("__default");


alert(meh);