JSFiddle - React, Tailwind, and code Playground

HTML

<p>
    Destination country:
    <select data-bind="options: availableCountries"></select>
</p>

JavaScript

var viewModel = {
        availableCountries: ko.observableArray(['France', 'Germany', 'Spain'])
    };
 
    // ... then later ...
    viewModel.availableCountries.push('China');