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I have an observable -- loading$ -- that outputs true when I want to show a loading overlay in the UI, and false when it's time to remove that overlay. The visibility is controlled with a CSS class.
When the Observable emits true, I want to add the CSS class to the <body>, and remove it on false.
html
<body class="">
<my-app>Angular app goes here</my-app>
</body>
As you can see, the <body> is outside of my Angular 2 app, so I cannot use property binding to change the class. This is what I currently do:
AppComponent.ts
loading$.subscribe(loading =>{
if(loading) document.querySelector('body').classList.add('loading');
else document.querySelector('body').classList.remove('loading');
});
This works well. The loading class is added/removed when the loading$ observable emits true/false. The problem is that I'd like to run my app in a web worker which means no access to the DOM. Plus, Angular recommends against manipulating the DOM directly.
How can I use Angular APIs to change <body>?
Angular 2, typescript 2, rxjs 5 beta 12
PS: This question looks promising, but the key link is dead. I've also seen a couple of suggestions that worked with Beta releases but are now obsolete (example)
430
If you want an uninterrupted animation by DOM replacement in the middle of bootstrapping the app then use the following approach.
Put the overlay after my-app element.
<my-app></my-app>
<div id="overlay"></div>
Add @HostBinding to class.ready in main component app.component.ts:
@HostBinding('class.ready') ready: boolean = false;
Change the property when the data is loaded with the initial call (splash is still visible when your screen is not fully rendered).
constructor(private contextService: ContextService) {
someService.initCall().then(r => this.ready = true);
}
Use CSS to hide the loader:
my-app.ready + .overlay {
animation: hideOverlay 1s forwards;
}
@keyframes hideOverlay {
0% {
opacity: 1;
}
100% {
opacity: 0;
visibility: hidden;
}
}
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