Update Ember CLI Ember.js apps and addons (and Glimmer.js apps)



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Update Ember CLI Ember.js apps and addons (and Glimmer.js apps)

You can run this either as a global executable available to all projects or an Ember CLI command in a single project.

Fetches list of codemods and instructions from ember-cli-update-codemods-manifest.


As a global executable:

npm install -g ember-cli-update

As an Ember CLI command:

ember install ember-cli-update

(You must commit the change to package.json before running the update command or else you get an error.)


Make sure your git working directory is clean before updating.

Inside your project directory, if you installed globally run


or if you installed as an Ember CLI command run

ember update

This will update your app or addon to the latest Ember CLI version. It does this by fetching the latest version and comparing it to your project's Ember CLI version. It then applies a diff of the changes from the latest version to your project. It will only modify the files if there are changes between your project's version and the latest version, and it will only change the section necessary, not the entire file.

This is different from the existing ember init command. That command tries to reset your project back to a brand new project. It removes all your changes and additions.

You will probably encounter merge conflicts, in which the default behavior is to let you resolve conflicts on your own. You can supply the --resolve-conflicts option to run your system's git merge tool if any conflicts are found.

This tool can also run codemods for you. The option --run-codemods will figure out what codemods apply to your current version of Ember.js, and download and run them for you.


(These examples assume you are using the global command.)

To update to the latest version of Ember CLI:


To update to a certain version of Ember CLI:

ember-cli-update --to 3.1.0

To run codemods:

(This should be run after running the normal update shown above, and after you've resolved any conflicts.)

ember-cli-update --run-codemods


Option Description Type Examples Default
--from Use a starting version that is different than what is in your package.json String "2.9.1"
--to Update to a version that isn't latest String "2.14.1" "~2.15" "latest" "beta" "latest"
--resolve-conflicts Automatically run git mergetool if conflicts found Boolean false
--run-codemods Run codemods to help update your code Boolean false
--reset Reset your code to the default blueprint at the new version Boolean false
--compare-only Show the changes between different versions without updating Boolean false
--stats-only Show all calculated values regarding your project Boolean false
--list-codemods List available codemods Boolean false
--create-custom-diff Create a personal diff using system .ember-cli Boolean false

Power User Guide

Let's update from Ember CLI 2.18.2 to Ember CLI 3.1.4

First, make sure you are on the latest ember-cli-update version for good measure.

npm install -g ember-cli-update

Then, run all compatible codemods against your current version. Since codemods are downloaded on the fly, they can be updated (and new ones added) without even getting a new version of ember-cli-update. Also, we may add additional codemods targeting your older version of Ember.js.

ember-cli-update --run-codemods

Assuming you are multiple versions behind of Ember CLI, you may want to update in stages. Unless you have a really simple app, updating in stages can help isolate upgrade issues.

ember-cli-update --to 3.0

Once you resolve conflicts and commit, You again want to run codemods. This is because new codemods targeting Ember.js 3.0 will now apply.

ember-cli-update --run-codemods

Now you are ready to update again. (If your final update is going to be the latest version of Ember CLI, you don't need the --to option.)

ember-cli-update --to 3.1

Again, after you resolve conflicts and commit, you want to run codemods because of new Ember.js 3.1 codemods.

ember-cli-update --run-codemods

And then you're done! You have a freshly updated app (or addon). As noted, you can consolidate these steps by doing a direct update, but then you may be confused if you encounter issues which version is to blame.


Need help using git mergetool? Here are some starting points:

If you made a mistake during the update/conflict resolution, run these commands to undo everything and get you back to before the update:

git reset --hard
git clean -f

If you notice ".orig" files lying around after a merge and don't want that behavior, run git config --global mergetool.keepBackup false.

To avoid being prompted "Hit return to start merge resolution tool (vimdiff):" for every conflict, set a merge tool like git config --global merge.tool "vimdiff".

If you run into an error like error: unrecognized input, you may need to update your git config color option like git config --global color.ui auto.


If you are getting an error or unexpected results, running the command with the debug flag:

  • Unix (global):   DEBUG=ember-cli-update,git-diff-apply ember-cli-update
  • Windows (global):   set DEBUG=ember-cli-update,git-diff-apply && ember-cli-update
  • Unix (command):   DEBUG=ember-cli-update,git-diff-apply ember update
  • Windows (command):   set DEBUG=ember-cli-update,git-diff-apply && ember update

will give you more detailed logging.