Question

var abc = {
    'a': 10,
    'b': 10,
    c: function() {
        //like if I have many many functions in c
        init_a();
        multiple();

        function init_a() {
            abc.a = 30;
        }

        function multiple() {
            alert(abc.a * abc.b);
        }

        function minus() {
            alert(abc.a - abc.b);
        }
        return {
            function myalert() {
                var result = abc.a + abc.b;
                alert(result);
            }
        }
    },
    d: function() {
        abc.c.myalert(); // ???  error??
        abc.c().myalert(); // ??? error??  **it run all functions in c but not just myalert, strange things happening...
    }

}
abc.d();

whats the correct syntax to call the ‘myalert()’ function in function d?

Answer 1

The myalert() function iswas local to abc.c(), so that’s not possible.

You could let c() return myalert() though:

c: function() {
    return function myalert() {
      // whatever
    }
}, d: function() {
    this.c()()
}

Note that the returned function doesn’t have to be named, i.e. return function() { .. }.

Update

If you want to call it like this.c().myalert(), then c() needs to return an object instead of the function directly:

c: function() {
    return {
        myalert: function() { ... }
    }
}

Update 2

Your c() function now contains other statements besides the declaration of myalert(). When called, init_a() and multiple() get called before it returns.

I would suggest refactoring your code, such as, move myalert() into the main object instead:

var abc = {
    a: 10,
    b: 10,
    c: function() { ... }
    myalert: function() { ... }
    d: function() {
        this.myalert();
    }
}