Using imports

[pingerofpong (John Leicht)]

If there’s any particular development topic you would like us to get into in a blog post, let us know!

When I upload an addon update to Firefox - as I have done before - all my files with module “imports” are rejected.

They test out OKAY in Firefox 61 (I’m not using developer or nightly). Do you know why the javascript modules might be rejected? Is it because I’m not using the .mjs extension in the filename? (I’m using .js)

[jorgev]

As far as I know ES6 imports are not supported in extension code at the moment.

[freaktechnik (Martin Giger)]

They are, see https://bugzilla.mozilla.org/show_bug.cgi?id=1394303 for context, but essentially you can use <script type="module"> in HTML to load your scripts as ES modules. I am not quite sure what versions this works in, though I guess it should be fine since Firefox 60.

[rugkx (rugk)]

Indeed, they should work, just some thing may not be optimal yet, such as this one:

Using ES6 modules in background scripts

I looked how one may use a background script es a new ES6 module. However, it seems to be very hard to easily do this. Usually you embed it like this. “background”: { “script”: [ “background.js” ] } However, with a ES6 module, this does not seem to work, because usually (e.g. when you embed it in a HTML you have to ad the attribute type="module". In a manifest.json this does not seem possible… So the problem has been discussed in this article and there a simple workaround has been suggeste…