Question

162

Knockout Computed Observable with parameters

rated 0 times [ 164] [ 2] / answers: 1 / hits: 9057 / 10 Years ago, wed, june 18, 2014, 12:00:00

Is it possible to provide a computed observable an extra parameter?

For example, something like this:

var ViewModel = function(first, last) {

    this.firstName = ko.observable(first);

    this.lastName = ko.observable(last);

    var self = this;

    this.fullName = ko.computed(function(separator) {

       return self.firstName() + ' ' + self.lastName();

    }, this);

};

And then in the html:

<div data-bind=text: fullName(' - ')></div>

My actual use case is far more complicated, but this is essentially what I'm trying to achieve, pass in a value in the html which is used as part of the computed function.

Failing this is there a way to make a ordinary function which takes parameters behave like a (computed) observable?

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denver

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3 Years ago

answered 10 Years ago irvingcarloe · Accepted Answer

You can create a function, which returns an computed variable. You can try something like this.

var ViewModel = function(first, last) {

    this.firstName = ko.observable(first);

    this.lastName = ko.observable(last);

    var self = this;

    this.fullName = function(separator){

    return ko.computed(function () {

            return self.firstName() + separator + self.lastName();}, this);

};

};



<div data-bind=text: ViewModel.fullName('-')></div>