JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/mustache.js/0.7.2/mustache.min.js"></script>
{{#isArray}}
I am an array!<br/>
    {{#test}} <li>{{.}}</li>{{/test}}
{{/isArray}}

{{^isArray}}
I am a string!<br/>
    {{test}}
{{/isArray}}

JavaScript

var data = {
    test: [ "test1", "test2", "test3" ]
}

var data2 = {
    test: "test"
}

var template = document.body.innerHTML;

if (data.test.pop) { data.isArray = 1; } else { data.isArray = 0; }
if (data2.test.pop) { data2.isArray = 1; } else { data2.isArray = 0; }

document.body.innerHTML = "<hr/>" + Mustache.render(template, data)
    + "<hr/>" + Mustache.render(template, data2);