JavaScript is now the world's most popular programming language, even though it started off as a side-kick to Java.

JavaScript remains the most used programming language among developers, but Python is the most studied – and Go the one that most coders want to switch to.

Built-in JavaScript objects and functions are ones you'll use all the time. Here's how to use Object, JSON, String, Math, Date, and console in your JavaScript programs.

Use popular 'grammar of data' syntax to filter and subset your two-dimensional JavaScript arrays and more. Here's how to use Arquero for data wrangling in Observable JavaScript and Node.js.