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Feature detect ES modules: both static import and dynamic import()
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<!-- | |
Complete feature detection for ES modules. Covers: | |
1. Static import: import * from './foo.js'; | |
2. Dynamic import(): import('./foo.js').then(module => {...}); | |
Demo: http://jsbin.com/tilisaledu/1/edit?html,output | |
Thanks to @_gsathya, @kevincennis, @rauschma, @malyw for the help. | |
--> | |
<body></body> | |
<!-- Remember: static modules have a fallback! --> | |
<script type="module"> | |
console.log('This browser supports <script type="module">'); | |
</script> | |
<script nomodule> | |
console.log('This browser DOES NOT support <script type="module">'); | |
</script> | |
<script> | |
// Feature detect static imports. | |
function supportsStaticImport() { | |
const script = document.createElement('script'); | |
return 'noModule' in script; | |
} | |
// Feature detect dynamic import(). | |
function supportsDynamicImport() { | |
try { | |
new Function('import("")'); | |
return true; | |
} catch (err) { | |
return false; | |
} | |
} | |
// Usage. | |
let el = document.createElement('pre'); | |
el.textContent = ` | |
Supports ES module static import: ${supportsStaticImport()} | |
Supports dynamic ES module import(): ${supportsDynamicImport()} | |
` | |
document.body.appendChild(el); | |
</script> |
A more concise supportsStaticImport script:
function supportsStaticImport() {
return 'noModule' in HTMLScriptElement.prototype;
}
@erikt9 feel free to submit this as an answer to the Stackoverflow question linked above.
https://developer.mozilla.org/en-US/docs/Web/API/HTMLScriptElement
function checkModuleSupport() {
if ('supports' in HTMLScriptElement) {
return HTMLScriptElement.supports('module');
}
return 'noModule' in document.createElement('script');
}
@mindhells you feel also free to submit this as an answer to the Stackoverflow question linked above.
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This is wrong.
e.g. Safari 10.1 supports type="module" but not the nomodule attribute
see https://gist.github.com/samthor/64b114e4a4f539915a95b91ffd340acc