JavaScript Dynamic Imports: Exploring a Powerful Feature | Tech Wiki Online

JavaScript Dynamic Imports: Exploring a Powerful Feature

tags: [“JavaScript”, “dynamic imports”, “code splitting”, “Next.js”, “ES Module”]

Dynamic imports are a new and upcoming feature in JavaScript that offer a range of possibilities. Recently, I had the opportunity to use dynamic imports in a Next.js application for code splitting. While they are similar to static imports, there are a few differences worth exploring.

To begin with, a static import of an ES Module’s default export follows this syntax:

import moment from 'moment'

In the case of named exports, object destructuring is used:

import { format } from 'date-fns'

However, static imports have some limitations. They can only be used at the top level of the file and cannot be loaded conditionally inside an if statement. Additionally, the package name cannot be determined at runtime.

This is where dynamic imports shine. They can be used in all of these scenarios! The syntax may be slightly different, but the possibilities are exciting.

Within modules, dynamic imports can be used like this:

const module = await import('module')

To use the default export, you need to call .default():

const moment = (await import('moment')).default()

On the other hand, named imports work as expected:

const { format } = await import('date-fns')

The good news is that you can start using dynamic imports today. The browser support for this feature is already quite good. Additionally, there is a Babel plugin available to handle dynamic imports if needed.

By leveraging the power of dynamic imports, you can enhance the flexibility and modularity of your JavaScript code. Start exploring this feature and unlock new possibilities in your projects.