cargdev/angular
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fix(elements): fire custom element output events during component initialization (#37570)

Browse Source 
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.ts

Fixes #36141

PR Close #37570
This commit is contained in:
George Kalpakas
2020-06-13 11:06:35 +03:00
committed by Andrew Kushnir
parent 78a44768e0
commit eba9dd364e
4 changed files with 126 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
packages/elements/test/component-factory-strategy_spec.ts
View File

@ -41,6 +41,33 @@ describe('ComponentFactoryNgElementStrategy', () => {
expect(strategyFactory.create(injector)).toBeTruthy();
});
describe('before connected', () => {
it('should allow subscribing to output events', () => {
const events: NgElementStrategyEvent[] = [];
strategy.events.subscribe(e => events.push(e));
// No events before connecting (since `componentRef` is not even on the strategy yet).
componentRef.instance.output1.next('output-1a');
componentRef.instance.output1.next('output-1b');
componentRef.instance.output2.next('output-2a');
expect(events).toEqual([]);
// No events upon connecting (since events are not cached/played back).
strategy.connect(document.createElement('div'));
expect(events).toEqual([]);
// Events emitted once connected.
componentRef.instance.output1.next('output-1c');
componentRef.instance.output1.next('output-1d');
componentRef.instance.output2.next('output-2b');
expect(events).toEqual([
{name: 'templateOutput1', value: 'output-1c'},
{name: 'templateOutput1', value: 'output-1d'},
{name: 'templateOutput2', value: 'output-2b'},
]);
});
});
describe('after connected', () => {
beforeEach(() => {
// Set up an initial value to make sure it is passed to the component