write to computed observable

[Arthur Enokyan]

i have a computed observable like this

    this.a = ko.observable(1);

    this.b = ko.observable(2);

    this.cc = ko.pureComputed({

            read: function () {

                return parseFloat(self.a() * self.b()).toFixed10(2);

            },

            write: function (value) {

                //?????????

            }

        });

how to write ? help please...

[Ian Yates]

Can you explain what you want to do?  

Pretend Knockout isn't involved...  If I set cc to 6 (for example), what should that do to the values of a & b?

Once you know that, it's a matter of just storing the values in a & b.  That's done by using  this.a(2)  and this.b(3)    to store 2 & 3 in observables a & b respectively.

[Arthur Enokyan]

i wonna do that

cc(6) => c() === 6, and do nothing with a and b 

and 

a(3), b(3) = > c() === 9

понедельник, 17 октября 2016 г., 15:41:57 UTC+3 пользователь Ian Yates написал:

[Michael Best]

You wouldn't then use a computed observable. I'd use three plain observables and subscribe to `a` and `b` to update `c`:

function updateCC() {
    cc(parseFloat(self.a() * self.b()).toFixed10(2));
}
this.a.subscribe(updateCC);
this.b.subscribe(updateCC);