JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.0/knockout-min.js"></script>
<p data-bind="text:ko.toJS(multiple)">
<p data-bind="text:ko.toJS(single)">

JavaScript

var self = {};

self.multiple = ko.observableArray();
self.single = ko.observableArray();

self.single.push(3);

self.multiple.push(JSON.parse(JSON.stringify(self.single())));

self.single.push(2);

console.log(ko.toJS(self.multiple));


ko.applyBindings(self)