JSFiddle - React, Tailwind, and code Playground

HTML

<div data-bind="text: computed"></div>
<button data-bind="click: updateOne">Update One</button>
<button data-bind="click: updateTwo">Update Two</button>

JavaScript

ViewModel = function() {
    this.observableOne = ko.observable("Initial state");
    this.observableTwo = ko.observable("Initial state");
    var observableTwoInitialState = this.observableTwo(); 
    
    this.computed = ko.computed(function() {
        return this.observableOne() + observableTwoInitialState;
    }, this);
};

ViewModel.prototype = {
    updateOne: function() {        
        this.observableOne(this.observableOne() + "ONE");
    },
    updateTwo: function() {
        this.observableTwo(this.observableTwo() + "TWO");
    }
};

ko.applyBindings(new ViewModel());