The problem

Recently I updated one of my EmberJS projects (v3.15.1...v3.23.0). And I got quite an unexpected error saying:

Error occurred while rendering:

- While rendering:
  application
    authenticated
      authenticated.admin
        authenticated.admin.items
          tabs
            authenticated.admin.items.stock
              form-radio
                form-field

Uncaught Error: Assertion Failed: You attempted to 
overwrite the built-in helper "array" which is 
not allowed. Please rename the helper.

The search

OK, I was pretty sure I did not write the helper myself. So since I knew that form-field and form-radio are from the amazing frontile addon, I tried to look there. I found the usage of array helper, but no definition.

So it either came from an addon or is native to respective Ember version. Since I did not know how to check the former, I went with the latter. And it turned out that Ember has native template array helper since version 3.8.0. So not much of a help here.

Luckily I remembered that since the beginning of the project I was using ember-composable-helpers addon that back in the days used to have also array template helper. So after a little bit of digging I found a PR with title: [Breaking Change] Refactor helpers for Octane (Ember 3.13+), which landed in v3.0.0 of ember-composable-helpers.

So next stop package.json files in my project and indeed I have found a pre v3.0.0 version:

"ember-composable-helpers": "^2.2.0",

Solution

tl;dr: If you bump into a "Uncaught Error: Assertion Failed: You attempted to overwrite the built-in helper "array" which is not allowed. Please rename the helper." error in your ember app/addon, chances are that you just need to run following command to make it work again:

ember install ember-composable-helpers

Photo by Sarah Kilian on Unsplash