Ember 3.8 Released

Today the Ember project is releasing version 3.8 of Ember.js, Ember Data, and Ember CLI. This release kicks off the 3.9 beta cycle for all sub-projects. We encourage our community (especially addon authors) to help test these beta builds and report any bugs before they are published as a final release in six weeks' time. The ember-try addon is a great way to continuously test your projects against the latest Ember releases.

You can read more about our general release process here:


Ember.js is the core framework for building ambitious web applications.

Changes in Ember.js 3.8

The 3.8.0 release is an Ember.js Long-Term Support candidate. In six weeks, the 3.8.x series will become the latest LTS release and six weeks after that the 3.4 LTS branch will no longer receive bugfix patches.

For more information about Ember's LTS policies, see the announcement blog post and builds page.

Ember.js 3.8 is an incremental, backwards compatible release of Ember with bugfixes, performance improvements, and minor deprecations. There are two (2) new features, one (1) deprecation, and six (6) bugfixes in this version.

New Features (2)

Element Modifier Manager (1 of 2)

A modifier manager is an object that is responsible for coordinating the lifecycle events that occurs when invoking, installing and updating an element modifier. This new feature is introduced as a very low-level API. Most likely you will never - as an Ember app developer - need to use this but it might come in handy for some add-on developers. In this way, the Ember app developers will benefit from this feature by subclassing these special modifiers provided by addons.

If you're interested in learning more about how to use this new feature, then please refer to the RFC.

Array helper (2 of 2)

Ember 3.8 introduces the {{array}} helper to create an array in a template. This helper works in similar fashion to the already existing {{hash}} helper.

The helper would be invoked as {{array arg1 ... argN}} and return the value [arg1, ..., argN]. For example, {{array 'a' 'b' 'c'}} would return the value ['a', 'b', 'c'].

Read the original RFC for more information.

Deprecations (1)

Deprecations are added to Ember.js when an API will be removed at a later date. Each deprecation has an entry in the deprecation guide describing the migration path to a more stable API. Deprecated public APIs are not removed until a major release of the framework.

Consider using the ember-cli-deprecation-workflow addon if you would like to upgrade your application without immediately addressing deprecations.

For more details on changes in Ember.js 3.8, please review the Ember.js 3.8.0 release page.

Component Manager Factory Function (1 of 1)

setComponentManager no longer takes a string to associate the custom component class and the component manager. Instead you must pass a factory function that produces an instance of the component manager. For more information please refer to the deprecations app

Ember Data

Ember Data is the official data persistence library for Ember.js applications.

Changes in Ember Data 3.8

While no new features or deprecations were introduced in Ember Data 3.8, there were a few fixes that users should find helpful:

  • documentation: updated release instructions, fixed broken links, clarified load/reload behavior, and added Reference and AdapterError documentation.
  • updated _scheduleFetch to use _fetchRecord for belongsTo relationship - without this, it would trigger one find-request per belongsTo relationship, instead of correctly coalescing them together.

For more details on changes in Ember Data 3.8, please review the Ember Data 3.8.0 release page.

Ember CLI

Ember CLI is the command line interface for managing and packaging Ember.js applications.

Upgrading Ember CLI

You may upgrade Ember CLI easily using the ember-cli-update project:

npm install -g ember-cli-update

This utility will help you to update your app or add-on to the latest Ember CLI version. You will probably encounter merge conflicts, in which the default behavior is to let you resolve conflicts on your own. For more information on the ember-cli-update project, see the github README.

While it is recommended to keep Ember CLI versions in sync with Ember and Ember Data, this is not required. After updating ember-cli, you can keep your current version(s) of Ember or Ember Data by editing package.json to revert the changes to the lines containing ember-source and ember-data.

Changes in Ember CLI 3.8

Here are some of the fixes in ember-cli 3.8 that community members may find useful to know about:

  • documentation: more links to the contributing guide were added, so users can more easily find out how to contribute
  • {{content-for}} was updated to allow the use of this on the same line if different types are specified (i.e., {{content-for 'head'}} {{content-for 'head-footer'}})
  • gitignore was updated to ignore Yarn .pnp files
  • the tests directory will be ignored when tests are turned off

For more details on each of these, and a full list of the changes in Ember CLI 3.8, as well as detailed upgrade instructions, please see the Ember CLI 3.8.0 release page.

Thank You

As a community-driven open-source project with an ambitious scope, each of these releases serve as a reminder that the Ember project would not have been possible without your continued support. We are extremely grateful to our contributors for their efforts.