Maybe.js

'use strict';

//data type
class Option { }
Option.None = class { toString() { return "None" } };
Option.Some = class { constructor(value) { this.some = value } toString() { return `Some:${this.some}` } };

//computation builder
let maybe = function (genFunc) {
    let gen = new genFunc();
    let ret;
    while (true) {
        let yieldable = gen.next(ret);        
        //"Return"
        if (yieldable.done) {
            return new Option.Some(yieldable.value);
        }
        //"Bind"
        if (yieldable.value instanceof Option.Some) {
            ret = yieldable.value.some;
        } else if (yieldable.value instanceof Option.None) {
            return yieldable.value;
        } else {
            throw new Error("Invalid value.");
        }
    }
}

//function work with the data type
let divide = function (top, bottom) {
    if (bottom === 0) {
        return new Option.None();
    } else {
        return new Option.Some(top / bottom);
    }
}

//usage
let res1 = maybe(function* () {
    let a = yield divide(24, 2);
    let b = yield divide(a, 0)
    let c = yield divide(b, 4)
    return c;
})

console.log("Result1:", res1.toString());
//output: Result: None                                                                                                                        

let res2 = maybe(function* () {
    let a = yield divide(24, 2);
    let b = yield divide(a, 3)
    let c = yield divide(b, 4)
    return c;
})
console.log("Result2:", res2.toString());

//output Result: Some:1