@avine/ng-if-non-nullish
v16.0.0
Published
Nullish coalescing operator as Angular structural directive and more...
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IfNonNullish
Nullish coalescing operator as Angular structural directive and more...
Demo
Check out demo here.
Installation
Import IfNonNullishDirective
(standalone directive) in your app.module.ts
:
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { IfNonNullishDirective } from '@avine/ng-if-non-nullish';
import { AppComponent } from './app.component';
@NgModule({
declarations: [AppComponent],
imports: [BrowserModule, IfNonNullishDirective],
bootstrap: [AppComponent],
})
export class AppModule {}
Use ifNonNullish
directive in your app.component.ts
:
import { Component } from '@angular/core';
import { interval, Observable } from 'rxjs';
import { map } from 'rxjs/operators';
@Component({
selector: 'app-root',
template: `<div *ifNonNullish="data$ | async as value">{{ value }}</div>`,
})
export class AppComponent {
data$: Observable<false | null> = interval(1000).pipe(map((i) => (i % 2 ? false : null)));
}
Unlike ngIf
directive, falsy values like false
, ""
or 0
are rendered.
Only nullish values like null
or undefined
are not rendered.
So, in the example above, false
will be rendered while null
will not.
Usage
Rendering data
Render data using "as" syntax or "implicit" syntax.
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
template: `
<div *ifNonNullish="data">{{ data }}</div>
<div *ifNonNullish="data as value">{{ value }}</div>
<div *ifNonNullish="data; let value">{{ value }}</div>
`,
})
export class AppComponent {
data: number | null = 0;
}
Rendering fallback template
Use fallback:
input to provide a templateRef
when data is nullish.
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
template: `
<div *ifNonNullish="data as value; fallback: fallbackTemplate">
{{ value }}
</div>
<ng-template #fallbackTemplate>
<i>Fallback</i>
</ng-template>
`,
})
export class AppComponent {
data = undefined;
}