JSFiddle - React, Tailwind, and code Playground

HTML

<script type="text/javascript"
src="http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars-c90cfe2.js"></script>
<div id="output"></div>

JavaScript

Handlebars.registerHelper('helper1', function (foo, text) {                                             
    return 'FOO: ' + foo + ',   FOO.TEXT: ' + text;
});

var tmpl = Handlebars.compile('{{helper1 foo foo.text}} ({{foo}}, {{foo.text}})<br/>');

document.getElementById('output').innerHTML += tmpl();

document.getElementById('output').innerHTML += tmpl({ foo: ['a']});

document.getElementById('output').innerHTML += tmpl({ foo: []});

document.getElementById('output').innerHTML += tmpl({ foo: {} });

document.getElementById('output').innerHTML += tmpl({ foo: 1 });

document.getElementById('output').innerHTML += tmpl({ foo: 2 });

// foo.text should be undefined? but we got false
document.getElementById('output').innerHTML += tmpl({ foo: false });

// foo.text should be undefined? but we got null
document.getElementById('output').innerHTML += tmpl({ foo: null });

// foo.text should be undefined? but we got 0
document.getElementById('output').innerHTML += tmpl({ foo: 0 });