Edit Since the original answer, Ecmascript, and Typescript (in 3.7) have both added the ?. (called the optional chaining operator) operator. See the PR for details. Original answer This is not a Typescript operator. Angular 2 has a safe navigation operator in templates. values?.listArray is equivalent to values != null ? values.listArray: null More info … Read more
Just remove the const modifier. const in an enum means the enum is fully erased during compilation. Const enum members are inlined at use sites. You can can’t index it by an arbitrary value. In other words, the following TypeScript code const enum Snack { Apple = 0, Banana = 1, Orange = 2, Other … Read more
delay() is used to introduce a delay between events emitted by the observable. But the observable never emits any event. It just errors immediately. What you’re looking for is retryWhen(), which allows deciding after how long to retry: RxJS 5: .retryWhen(errors => errors.delay(1000).take(10)) RxJS 6: import { retryWhen, delay, take } from ‘rxjs/operators’ someFunction().pipe( // … Read more
You are almost there, simply provide both SampleService and config in your module like below: export class SampleModule { static forRoot(config: CustomConfig): ModuleWithProviders<SampleModule> { // User config get logged here console.log(config); return { ngModule: SampleModule, providers: [SampleService, {provide: ‘config’, useValue: config}] }; } } @Injectable() export class SampleService { foo: string; constructor(@Inject(‘config’) private config:CustomConfig) { … Read more
To get data from an observable, you need to subscribe: this.singleEvents$.subscribe(event => this.event = event); In the template you can directly bind to observables using the async pipe: {{singleEvents$ | async}}
Generic functions in TypeScript act as a function representing every possible specification of its generic type parameters, since it’s the caller of the function that specifies the type parameter, not the implementer: type GenericFunction = <T>(x: T) => T; const cantDoThis: GenericFunction = (x: string) => x.toUpperCase(); // error! // doesn’t work for every T … Read more
You can use an intersection of two interfaces: interface Api<T> { [key: string]: T[]; } type ApiType<T> = Api<T> & { meta: Meta; } declare let x: ApiType<string>; let a = x.meta // type of `a` is `Meta` let b = x[“meta”]; // type of `b` is `Meta` let p = x[“someotherindex”] // type of … Read more
Try to use an approach described in here https://docs.nestjs.com/techniques/security#cors const app = await NestFactory.create(ApplicationModule); app.enableCors(); await app.listen(3000);
edit If you use angular 9.1.6 it should be fine now npm update @angular/cli @angular/core original post Something is broken in Angular 9.1.5 – if you run the following it should work: npm install @angular/core@9.1.4 @angular/animations@9.1.4 @angular/common@9.1.4 @angular/forms@9.1.4 @angular/platform-browser@9.1.4 @angular/router@9.1.4 @angular/platform-browser-dynamic@9.1.4 @angular/compiler@9.1.4 @angular/compiler-cli@9.1.4 @angular/language-service@9.1.4 ng build Just spent about 4-5 hours trying to fix it … Read more
You can get the ViewContainerRef of the current component by or from an element in the view of the current component @Component({ selector: ‘…’, directives: [OtherComponent, FooComponent], template: ` <other-component></other-component> <foo-component #foo></foo-component> <div #div></div>` }) export class SomeComponent { // `ViewContainerRef` from an element in the view @ViewChild(OtherComponent, {read: ViewContainerRef}) other; @ViewChild(‘foo’, {read: ViewContainerRef}) foo; … Read more