According to Stack Overflows 2019 developer survey JavaScript is the most popular language among developers for the 7th Year in a row. Many of these JavaScript developers learned the language in 2016 or later. This means there are lots of web developers who learned JavaScript after 2015 when ECMAScript 6 or ES6 released. In this blog post I hope to compair variable declarations. Hopefully this will help newer developers adapt to working with legacy code more easily and quickly.