Node.JS had that ability for a while before it was incorporated in JavaScript with a feature called ‘modules.’ Eventually, they made it to the language itself and the browsers.

Beyond the usual quick tips, let's look at both the business case and the technical side of keeping React bundles lean.

ECMAScript modules, aka ES modules or ESM, is the official JavaScript module syntax. As such, it is not technically a tool, but it has broad implications for JS development and tools.