Testing ES6 fat arrow and lodash debounce together

ES6-Debounce-Test.js

function foo(s) { console.log(s); };

let d = _.debounce((s) => foo(s), 500);

$newEl = document.createElement('button');
$newEl.onclick = d;

$target = document.body;
$target.insertBefore($newEl, $target.childNodes[0]);