The custom element implementation previously used a custom code path for
setting inputs, which contained bespoke code for writing input properties,
detecting whether inputs actually change, marking the component dirty,
scheduling and running CD, invoking `ngOnChanges`, etc. This custom logic
had several downsides:
* Its behavior different from how Angular components behave in a normal
template.
For example, inputs setters were invoked in `NgZone.run`, which (when
called from outside the zone) would trigger synchronous CD in the
component, _without_ calling `ngOnChanges`. Only when the custom rAF-
scheduled `detectChanges()` call triggered would `ngOnChanges` be called.
* CD always ran multiple times, because of the above. `NgZone.run` would
trigger CD, and then separately the scheduler would trigger CD.
* Signal inputs were not supported, since inputs were set via direct
property writes.
This change refactors the custom element implementation with two changes:
1. `ComponentRef.setInput` is used instead of a custom code path for
writing inputs.
This allows us to drop all the custom logic related to managing
`ngOnChanges`, since `setInput` does that under the hood. `ngOnChanges`
behavior now matches how the component would behave when _not_ rendered
as a custom element.
2. The custom rAF-based CD scheduler is removed in favor of the main Angular
scheduler, which now handles custom elements as necessary.
Running `NgZone.run` is sufficient to trigger CD when zones are used, and
the hybrid zoneless scheduler now ensures CD is scheduled when `setInput` is
called even with no ZoneJS enabled. As a result, the dedicated elements
scheduler is now only used when Angular's built-in scheduler is disabled.
As a concession to backwards compatibility, the element's view is also
marked for refresh when an input changes. Doing this allows CD to revisit
the element even if it becomes dirty during CD, mimicking how it would be
detected by the former elements scheduler unconditionally refreshing the
view a second time.
As a part of this change, the elements tests have been significantly
refactored. Previously all of Angular was faked/spied, which had a number
of downsides. For example, there were tests which asserted that change
detection only happens once when setting multiple inputs. This wasn't
actually the case (because of `NgZone.run` - see logic above) but the test
didn't catch the issue because it was only spying on `detectChanges()` which
isn't called from `ApplicationRef.tick()`. Even the components were fake.
Now, the tests use real Angular components and factories. They've also been
updated to not use `fakeAsync`.
A number of tests have been disabled, which were previously asserting
behavior that wasn't matching what was actually happening (as above). Other
tests were disabled due to real differences with `ngOnChanges` behavior,
where the current behavior could be seen as a bug.
Fixes#53981
BREAKING CHANGE: as part of switching away from custom CD behavior to the
hybrid scheduler, timing of change detection around custom elements has
changed subtly. These changes make elements more efficient, but can cause
tests which encoded assumptions about how or when elements would be checked
to require updating.
PR Close#56728
the createCustomEvent function's pupose is to create customEvents
even on browsers where `CustomEvent` is not a constructor,
`CustomEvent` is currently available in all supported browsers (since
IE11 support has ended), so remove the function as it is no longer
needed
PR Close#44703
In combination with the TS `noImplicitOverride` compatibility changes,
we also want to follow the best-practice of adding `override` to
members which are implemented as part of abstract classes. This
commit fixes all instances which will be flagged as part of the
custom `no-implicit-override-abstract` TSLint rule.
PR Close#42512
Support for IE<11 is being removed in v11. PR #39090 removed some code
that was no longer needed.
Now that there are no longer multiple code-paths (which was previously
needed for IE<11 support), this commit simplifies the code further (for
example, to avoid unnecessary functions calls and to avoid iterating
over a component's inputs multiple times).
PR Close#39265
Previously, event listeners for component output events attached on an
Angular custom element before inserting it into the DOM (i.e. before
instantiating the underlying component) didn't fire for events emitted
during initialization lifecycle hooks, such as `ngAfterContentInit`,
`ngAfterViewInit`, `ngOnChanges` (initial call) and `ngOnInit`.
The reason was that `NgElementImpl` [subscribed to events][1] _after_
calling [ngElementStrategy#connect()][2], which is where the
[initial change detection][3] takes place (running the initialization
lifecycle hooks).
This commit fixes this by:
1. Ensuring `ComponentNgElementStrategy#events` is defined and available
for subscribing to, even before instantiating the component.
2. Changing `NgElementImpl` to subscribe to `NgElementStrategy#events`
(if available) before calling `NgElementStrategy#connect()` (which
initializes the component instance) if available.
3. Falling back to the old behavior (subscribing to `events` after
calling `connect()` for strategies that do not initialize `events`
before their `connect()` is run).
NOTE:
By falling back to the old behavior when `NgElementStrategy#events` is
not initialized before calling `NgElementStrategy#connect()`, we avoid
breaking existing custom `NgElementStrategy` implementations (with
@remackgeek's [ElementZoneStrategy][4] being a commonly used example).
Jira issue: [FW-2010](https://angular-team.atlassian.net/browse/FW-2010)
[1]: c0143cb2ab/packages/elements/src/create-custom-element.ts (L167-L170)
[2]: c0143cb2ab/packages/elements/src/create-custom-element.ts (L164)
[3]: c0143cb2ab/packages/elements/src/component-factory-strategy.ts (L158)
[4]: f1b6699495/projects/elements-zone-strategy/src/lib/element-zone-strategy.tsFixes#36141
PR Close#37570
Build-optimizer currently uses TypeScript 3.6 which is unable to resolve an 'accessor' in 'getTypeOfVariableOrParameterOrPropertyWorker'.
Unfortunately, in Build optimizer we cannot update the version of TypeScript because of https://github.com/microsoft/TypeScript/issues/38412
PR Close#37456
Previously, event listeners for component output events attached on an
Angular custom element before inserting it into the DOM (i.e. before
instantiating the underlying component) didn't fire for events emitted
during initialization lifecycle hooks, such as `ngAfterContentInit`,
`ngAfterViewInit`, `ngOnChanges` (initial call) and `ngOnInit`.
The reason was that that `NgElementImpl` [subscribed to events][1]
_after_ calling [ngElementStrategy#connect()][2], which is where the
[initial change detection][3] takes place (running the initialization
lifecycle hooks).
This commit fixes this by:
1. Ensuring `ComponentNgElementStrategy#events` is defined and available
for subscribing to, even before instantiating the component.
2. Ensuring `NgElementImpl` subscribes to `NgElementStrategy#events`
before calling `NgElementStrategy#connect()` (which initializes the
component instance).
Jira issue: [FW-2010](https://angular-team.atlassian.net/browse/FW-2010)
[1]: c0143cb2ab/packages/elements/src/create-custom-element.ts (L167-L170)
[2]: c0143cb2ab/packages/elements/src/create-custom-element.ts (L164)
[3]: c0143cb2ab/packages/elements/src/component-factory-strategy.ts (L158)Fixes#36141
PR Close#36161
Previously, the correct behavior of Angular custom elements relied on
the constructor being called (and thus the `injector` property being
initialized). However, some polyfills (e.g. `document-register-element`)
do not call the constructor of custom elements, which resulted in the
`injector` property being undefined and the `NgElementStrategy` failing
to be instantiated.
This commit fixes it by being tolerant to the `injector` property being
undefined and falling back to the injector passed to the
`createCustomElement()` config.
NOTE:
We don't have proper tests exercising the situation where the
constructor is not called. For now this is tested using a Google
internal test suite (which is how this issue was caught).
This commit also adds a rudimentary unit test to emulate this situation.
PR Close#36114
Previously, if an element started out as a regular `HTMLElement` (not a
Custom Element) and was later upgraded to a Custom Element, any
properties corresponding to component inputs that were set on the
element before upgrading it would not be captured correctly and thus not
reflected on the instantiated component.
This commit fixes it by ensuring that such properties are captured
correctly.
Jira issue: [FW-2006](https://angular-team.atlassian.net/browse/FW-2006)
Fixes#30848Closes#31416
PR Close#36114
Previously, we had to check whether `NgElementStrategy` had been
instantiated before accessing it. This was tedious and error prone,
since it was easy to forget to add the check in new call sites.
This commit switches to using a getter, so that the check has to be
performed in one place and is transparent to call sites (including any
future ones).
PR Close#36114
`createCustomElements()` creates some getters/setters for properties
corresponding to component inputs that delegate to the
`NgElementStrategy`. However, it is not guaranteed that the element's
`NgElementStrategy` will have been created when these getters/setters
are called, because some polyfills (e.g. `document-register-element`) do
not call the constructor.
Previously, trying to get/set input properties before connecting the
element to the DOM (via `connectedCallback()`) would fail due to
`NgElementStrategy` not being created.
This commit ensures that the `NgElementStrategy` is always created
before used inside the input property getters/setters (similar to how it
is done for other methods of `NgElement`).
Mentioned in https://github.com/angular/angular/pull/31416/files#r300326698.
PR Close#36114
This commit adds support in the Angular monorepo and in the Angular
compiler(s) for TypeScript 3.8. All packages can now compile with
TS 3.8.
For most of the repo, only a handful few typings adjustments were needed:
* TS 3.8 has a new `CustomElementConstructor` DOM type, which enforces a
zero-argument constructor. The `NgElementConstructor` type previously
declared a required `injector` argument despite the fact that its
implementation allowed `injector` to be optional. The interface type was
updated to reflect the optionality of the argument.
* Certain error messages were changed, and expectations in tests were
updated as a result.
* tsserver (part of language server) now returns performance information in
responses, so test expectations were changed to only assert on the actual
body content of responses.
For compiler-cli and schematics (which use the TypeScript AST) a major
breaking change was the introduction of the export form:
```typescript
export * as foo from 'bar';
```
This is a `ts.NamespaceExport`, and the `exportClause` of a
`ts.ExportDeclaration` can now take this type as well as `ts.NamedExports`.
This broke a lot of places where `exportClause` was assumed to be
`ts.NamedExports`.
For the most part these breakages were in cases where it is not necessary
to handle the new `ts.NamedExports` anyway. ngtsc's design uses the
`ts.TypeChecker` APIs to understand syntax and so automatically supports the
new form of exports.
The View Engine compiler on the other hand extracts TS structures into
metadata.json files, and that format was not designed for namespaced
exports. As a result it will take a nontrivial amount of work if we want to
support such exports in View Engine. For now, these new exports are not
accounted for in metadata.json, and so using them in "folded" Angular
expressions will result in errors (probably claiming that the referenced
exported namespace doesn't exist).
Care was taken to only use TS APIs which are present in 3.7/3.6, as Angular
needs to remain compatible with these for the time being.
This commit does not update angular.io.
PR Close#35864
All errors for existing fields have been detected and suppressed with a
`!` assertion.
Issue/24571 is tracking proper clean up of those instances.
One-line change required in ivy/compilation.ts, because it appears that
the new syntax causes tsickle emitted node to no longer track their
original sourceFiles.
PR Close#24572
Closure compiler with type based optimizations has a bug where externs for inherited static fields are not being honored. For Angular Elements this meant that 'observedAttributes' static field which is marked as an extern for the base HTMLElement class was getting renamed.
This commit works around the bug by using quoted access of 'observedAttributes' that explicitly prevents the renaming.
PR Close#23843
