JSFiddle - React, Tailwind, and code Playground

HTML

<p data-bind="audio: {value: someobservable, sound:'http://www.w3schools.com/TAGs/horse.ogg'}">SOme test</p>
<button data-bind="click: click">Click</button>

JavaScript

ko.bindingHandlers.audio = {
    init: function (element, valueAccessor, allBindings, viewModel, bindingContext) {
        var config = ko.unwrap(valueAccessor());
        var file = config.sound;
        var observable = config.value;
        observable.subscribe(function () {
            var audio = new Audio(file);
            audio.play();
        });
    }
};

ko.applyBindings({
    someobservable: ko.observable(),
    click: function () {
        this.someobservable('change');
    }
})