This content originally appeared on web.dev and was authored by Thomas Steiner
ES modules are a modern way to include and reuse JavaScript code in web applications. They are supported by modern browsers and provide several benefits over older, non-modular approaches to JavaScript development.
A modern way to use ES modules is with the <script type="importmap"> tag. This tag allows you to
define a mapping of external module names to their corresponding URLs, which makes it easier to
include and use external modules in your code.
To use the <script type="importmap"> approach, you first need to add it to the <head> section of
your HTML document. Inside the tag, you can define a JSON object that maps module names to their
corresponding URLs. For example:
<script type="importmap">
{
"imports": {
"lodash": "https://unpkg.com/lodash@4.17.21/lodash.js"
}
}
</script>This code defines a single external module named "lodash" and maps it to the URL of the lodash
library on the unpkg CDN. With this mapping in place, you can now use the import keyword to
include the lodash library in your code. Note that the import keyword is only available inside a
script tag with the type="module" attribute.
<script type="module">
import _ from 'lodash';
console.log(_.map([1, 2, 3], (n) => n * 2));
</script>Using the <script type="importmap"> tag and the import keyword provides several benefits over
older, non-modular approaches to JavaScript development. It allows you to clearly and explicitly
specify the external modules your code depends on, which makes it easier to understand and maintain
your code. Overall, using ES modules with the <script type="importmap"> tag is a modern and
powerful way to include and reuse JavaScript code in web applications. You can feature-detect
support as follows:
if (HTMLScriptElement.supports('importmap')) {
// The importmap feature is supported.
}- chrome 89, Supported 89
- firefox 108, Supported 108
- edge 89, Supported 89
- safari, Not supported ×
Further reading #
Acknowledgements #
Hero image by CHUTTERSNAP on Unsplash.
This content originally appeared on web.dev and was authored by Thomas Steiner
Thomas Steiner | Sciencx (2023-03-28T00:00:00+00:00) JavaScript import maps are now supported cross-browser. Retrieved from https://www.scien.cx/2023/03/28/javascript-import-maps-are-now-supported-cross-browser/
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