How is the browser downgraded if it does not support dynamic import?

[lzxb]

What should I do if my browser supports module but does not support dynamic import?

[guybedford]

If your browser does not support dynamic import, you should use an older version of es-module-shims that polyfills dynamic import. Perhaps try version 1.10.1.

[lzxb]

Is there any solution that is compatible with the latest version?

[lzxb]

I am building a web application framework using importmap and ESM, and I am thinking about how to make it compatible with lower versions of browsers

[lzxb]

I saw that version 2.0 is based on browser support for dynamic import() compatibility

[lzxb]

Can es-module-shims provide a callback function when compatibility is not available?

I will provide a page similar to this

[guybedford]

Very few browsers do not support dynamic import, so the minimum versions here are actually very low.

See https://caniuse.com/es6-module-dynamic-import.

The main thing is Firefox before 67 and Safari before 11.1, IE, or edge below 79.

I'd be surprised if you find many users here at all.

[lzxb]

We have many users in China and often receive feedback. I hope there is a hook that can tell the browser that it is no longer supported and prompt users to upgrade their browser

[lzxb]

If es-module-shims didn't tell me, I don't know if it's working.

[guybedford]

You might try adding something like the following to the top of the page:

<script>
(function () {
  var dynamicImportSupported = false;
  try { eval("import(m)") } catch (e) { if (e instanceof ReferenceError) dynamicImportSupported = true }
  if (!dynamicImportSupported) {
    alert('This browser does not support modern JavaScript modules, make sure to use Chrome 79+, Firefox 67+, Safari 11.1+');
  }
})();
</script>