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Liam DeBeasi 57e2476370 feat(angular): ship Ionic components as Angular standalone components (#28311)
Issue number: N/A

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<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

**1. Bundle Size Reductions**

All Ionic UI components and Ionicons are added to the final bundle of an
Ionic Angular application. This is because all components and icons are
lazily loaded as needed. This prevents the compiler from properly tree
shaking applications. This does not cause all components and icons to be
loaded on application start, but it does increase the size of the final
app output that all users need to download.

**Related Issues**

https://github.com/ionic-team/ionicons/issues/910

https://github.com/ionic-team/ionicons/issues/536

https://github.com/ionic-team/ionic-framework/issues/27280

https://github.com/ionic-team/ionic-framework/issues/24352

**2. Standalone Component Support**

Standalone Components are a stable API as of Angular 15. The Ionic
starter apps on the CLI have NgModule and Standalone options, but all of
the Ionic components are still lazily/dynamically loaded using
`IonicModule`. Standalone components in Ionic also enable support for
new Angular features such as bundling with ESBuild instead of Webpack.
ESBuild does not work in Ionic Angular right now because components
cannot be statically analyzed since they are dynamically imported.

We added preliminary support for standalone components in Ionic v6.3.0.
This enabled developers to use their own custom standalone components
when routing with `ion-router-outlet`. However, we did not ship
standalone components for Ionic's UI components.

**Related Issues**

https://github.com/ionic-team/ionic-framework/issues/25404

https://github.com/ionic-team/ionic-framework/issues/27251

https://github.com/ionic-team/ionic-framework/issues/27387

**3. Faster Component Load Times**

Since Ionic Angular components are lazily loaded, they also need to be
hydrated. However, this hydration does not happen immediately which
prevents components from being usable for multiple frames.

**Related Issues**

https://github.com/ionic-team/ionic-framework/issues/24352

https://github.com/ionic-team/ionic-framework/issues/26474

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Ionic components and directives are accessible as Angular standalone
components/directives

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

Associated documentation branch:
https://github.com/ionic-team/ionic-docs/tree/feature-7.5

---------

Co-authored-by: Maria Hutt <thetaPC@users.noreply.github.com>
Co-authored-by: Sean Perkins <sean@ionic.io>
Co-authored-by: Amanda Johnston <90629384+amandaejohnston@users.noreply.github.com>
Co-authored-by: Maria Hutt <maria@ionic.io>
Co-authored-by: Sean Perkins <13732623+sean-perkins@users.noreply.github.com>
2023-10-10 13:06:23 -04:00
..

Angular E2E Test Apps

Ionic Framework supports multiple versions of Angular. As a result, we need to verify that Ionic works correctly with each of these Angular versions.

Syncing Local Changes

The Angular test app supports syncing your locally built changes for validation.

  1. Build the core and packages/angular directories using npm run build.
  2. Build the Angular test app.
  3. Navigate to the built test app directory (e.g. packages/angular/test/build/ng14).
  4. Install dependencies using npm install.
  5. Sync your local changes using npm run sync.

From here you can either build the application or start a local dev server. When re-syncing changes, you will need to wipe or disable the application cache.

Application Cache

Angular CLI creates a cache of several files on disk by default in the .angular directory. This decreases the time taken to build the test application. However, the cache makes it difficult to quickly sync and check local changes of Ionic. As a result, the .angular cache is disabled by default in the test app projects.

See https://angular.io/cli/cache for more information.

Disable Cache

ng cache disable

Note

You may need to manually remove the .angular directory once after running this command.

Enable Cache

ng cache enable

Note

You will need to delete the .angular cache and restart the dev server every time you want to sync local changes of Ionic.

Test App Build Structure

Note

Please confirm your current directory as packages/angular/test before proceeding with any of the following commands.

Unlike other test applications, these test apps are broken up into multiple directories. These directories are then combined to create a single application. This allows us to share common application code, tests, etc so that each app is being tested the same way. Below details the different pieces that help create a single test application.

apps - This directory contains partial applications for each version of Angular we want to test. Typically these directories contain new package.json files, angular.json files, and more. If you have code that is specific to a particular version of Angular, put it in this directory.

base - This directory contains the base application that each test app will use. This is where tests, application logic, and more live. If you have code that needs to be run on every test app, put it in this directory.

build - When the apps and base directories are merged, the final result is put in this directory. The build directory should never be committed to git.

build.sh - This is the script that merges the apps and base directories and places the built application in the build directory.

Usage:

# Build a test app using apps/ng14 as a reference
./build.sh ng14

How to modify test apps

To add new tests, components, or pages, modify the base project. This ensures that tests are run for every tested version.

If you want to add a version-specific change, add the change inside of the appropriate projects in apps. Be sure to replicate the directory structure. For example, if you are adding a new E2E test file called test.spec.ts in apps/ng14, make sure you place the file in apps/ng14/e2e/src/test.spec.ts.

Version-specific tests

If you need to add E2E tests that are only run on a specific version of the JS Framework, replicate the VersionTest component on each partial application. This ensures that tests for framework version X do not get run for framework version Y.

Testing Lazy Loaded Ionic Components

Tests for lazy loaded Ionic UI components should only be added under the /lazy route. This ensures the IonicModule is added.

Testing Standalone Ionic Components

Tests for standalone Ionic UI components should only be added under the /standalone route. This allows for an isolated environment where the lazy loaded IonicModule is not initialized. The standalone components use Stencil's custom element bundle instead of the lazy loaded bundle. If IonicModule is initialized then the Stencil components will fall back to using the lazy loaded implementation instead of the custom elements bundle implementation.

Adding New Test Apps

As we add support for new versions of Angular, we will also need to update this directory to test against new applications. The following steps can serve as a guide for adding new apps:

  1. Navigate to the built app for the most recent version of Angular that Ionic tests.
  2. Update the application by following the steps on https://update.angular.io/.
  3. Make note of any files that changed during the upgrade (package.json, package-lock.json, angular.json, etc).
  4. Copy the changed files to a new directory in apps.
  5. Add a new entry to the matrix for test-core-angular in ./github/workflows/build.yml. This will allow the new test app to run against all PRs.
  6. Commit these changes and push.

Example:

In this example, we are going to add the Angular 14 test app.

  1. Build the Angular 13 test app using ./build.sh ng13.
  2. Navigate to build/ng13.
  3. Perform the upgrade steps on https://update.angular.io/. The "From" field should say "13.0" and the "To" field should say "14.0".

Note: You may encounter some other peer dependency issues not covered by the Angular Upgrade Guide. These peer dependency issues can be resolved manually by updating the installed version of each dependency.

  1. Observe that the output of the Angular upgrade indicates that the following files were modified:

angular.json package-lock.json package.json tsconfig.json src/app/form/form.component.ts src/app/modal-example/modal-example.component.ts

  1. Create a directory in apps named ng14.
  2. Copy the modified files to the apps/ng14 directory.
  3. Open ./github/workflows/build.yml and find the test-angular-e2e job.
  4. Find the apps field under matrix.
  5. Add "ng14" to the apps field.
  6. Commit these changes and push.