CODEWITHSUNDEEP
javascriptjqueryknockout.js
Conner
Conner

Reputation: 813

Knockout: How to do a two-way binding for two number inputs

I just recently picked up KO and want to do something similar to the following.

There are two inputs and they change one another.

HTML:

<input data-bind="value: var1" type="text">
<input data-bind-"value: var2" type="text">

Script:

function DataViewModel() {
        var self = this;
        self.price = 5;
        self.var1 = ko.observable(0);
        self.var2 = ko.computed({
            read: function () {
                if(self.var1() <= 0) {
                    return 0;
                }
                return (self.var1 - 1) / self.price;
            },
            write: function (value) {
                self.var1((Number(value) + 1) * self.price); 
                // Value = 7.8, output is 44 for var1,
                // var2 changes to 8.6. Desired is 40 for var1 and 7.8 for var2.
            },
            owner: self
        });
    }
ko.applyBindings(new DataViewModel());

When 40 is inputed into var1, var2 shows 7.8. But when 7.8 is inputed into var2, var1 updates to 44 instead of 40 and the var2 changes to 8.6.

I want var2 to remain what was inputed instead of undergoing the read function.

http://jsfiddle.net/tyq7ejdh/2/

Upvotes: 0

Views: 55

Answers (1)

Mox Shah
Mox Shah

Reputation: 3015

This expression is incorrect

   write: function (value) {
                self.var1((value+1) * self.price);
            },

Try updating like this

   write: function (value) {
                self.var1((value * self.price) + 1);
            },

Fiddle

Upvotes: 1

Related Questions