# Ember 3.x and browser support

**URL:** <https://discuss.emberjs.com/t/ember-3-x-and-browser-support/17890>\
**Category:** Ember CLI\
**Created:** [May 17, 2020, 8:18am UTC](https://discuss.emberjs.com/t/ember-3-x-and-browser-support/17890 "2020-05-17T08:18:38Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![zion54321](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/zion54321/32/17053_2.png) [@zion54321](https://discuss.emberjs.com/u/zion54321)\
**Post date:** [May 17, 2020, 8:18am UTC](https://discuss.emberjs.com/t/ember-3-x-and-browser-support/17890/1 "2020-05-17T08:18:38Z")

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In some not fresh browser like Firefox 49 I have `SyntaxError` and I see blank page . Did’t find any information about browser support, so how to understand there is a problems in libraries, build configs or this browser not supported at all in ember 3.x. I wanna support browser like Firefox 49 and above, so ready for any information helps me to research this problem or just understand what happen. In new browser works like a charm

Error example from Firefox 49: SyntaxError: missing = in const declarationvendor-71a40b93ddeec9a3420d0124213d88aa.js:7394:10 ReferenceError: define is not defined

Environment: DEBUG: Ember : 3.18.0 DEBUG: Ember Data : 3.17.0

**UPDATE**

after debugging the problem was found in custom `app.import`, looks like this libs not go through `babel`.

```
app.import('node_modules/...some modeule', {
     using: [
       {
        transformation: 'fastbootShim'
      }
     ]
  });

```

Is there a way run `Babel` on custom imoprt?

---

<div class="post-metadata">

**Author:** ![ef4](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/ef4/32/13470_2.png) [@ef4](https://discuss.emberjs.com/u/ef4)\
**Post date:** [May 18, 2020, 7:42pm UTC](https://discuss.emberjs.com/t/ember-3-x-and-browser-support/17890/2 "2020-05-18T19:42:07Z")

</div>

I don’t know of any prebuilt way to run `app.import` through babel. If you can switch to ember-auto-import, that does automatically go through babel-preset-env to respect your browser targets.

There’s not an equivalent of “fastbootShim” for ember-auto-import, but you can use `import()` to only try to load the library when not in fastboot.