Can ES6's module loader also load assets (html/css/...)
If you use SystemJS then you can load assets by using plugins:
// Will generate a <link> element for my/file.css
System.import('my/file.css!')
.then(() => console.log('CSS file loaded'));
Alternatively, you can use an import
statement. This will make sure that the CSS file is loaded before the your script executes:
import 'my/file.css!';
Finally, you can retrieve the contents of the file using the text plugin:
import cssContent from 'my/file.css!text';
console.log('CSS file contents: ', cssContent);
Another option is to add the css as a dependency in JSPM config files. Basically adding the dependency in the specific package .json file and then running 'jspm install' which will add the override to package.js & jspm.config.js
I know you mentioned ES6 modules, but as that does not appear to support CSS natively, if you're looking for something standards-based to load resources dynamically and wish for something possibly somewhat less unpleasant than XMLHttpRequest
, the new Fetch API might be used like this:
var myStylesheets = ['myStyles1.css', 'myStyles2.css'];
Promise.all(myStylesheets.map(url => fetch(url))).
then(arr => Promise.all(arr.map(url => url.text()))).
then(arr => {
var style = document.createElement('style');
style.textContent = arr.reduce(
(prev, fileContents) => prev + fileContents, ''
);
document.head.appendChild(style);
}).then(() => {
// Do whatever now
});
This is even cleaner with async functions:
var myStylesheets = ['myStyles1.css', 'myStyles2.css'];
async function loadStyles(stylesheets) {
let arr = await Promise.all(stylesheets.map(url => fetch(url)))
arr = await Promise.all(arr.map(url => url.text()))
const style = document.createElement('style')
style.textContent = arr.reduce(
(prev, fileContents) => prev + fileContents, ''
)
document.head.appendChild(style);
// Do whatever now
}
loadStyles(myStylesheets)
For other resource types, you can use the blob()
method for images, and pending ES6 modules support, eval()
for JavaScript, etc.