You can use this type of constructors: { new (): ClassType }. class MyManager<T> { private cls: { new(): T }; constructor(cls: { new(): T }) { this.cls = cls; } createInstance(): T { return new this.cls(); } } class MyClass {} let test = new MyManager(MyClass); let a = test.createInstance(); console.log(a instanceof MyClass); // … Read more
Both module resolution strategies that tsc provides don’t support such a behavior. What your desired import statement import * as mylib from “./source/”; is actually doing is to perform checks in this order: 1. (does package.json have a typings key? If so, import this file) 2. import * as mylib from “./source/index.ts”; 3. import * … Read more
EDIT As of TypeScript 2.8 this is officially possible with ReturnType<T>. type T10 = ReturnType<() => string>; // string type T11 = ReturnType<(s: string) => void>; // void type T12 = ReturnType<(<T>() => T)>; // {} type T13 = ReturnType<(<T extends U, U extends number[]>() => T)>; // number[] See this pull request to Microsoft/TypeScript … Read more
I could solve this by injecting MyService within each and every component and use that argument for the super() call but that’s definetly some kind of absurd. It’s not absurd. This is how constructors and constructor injection works. Every injectable class has to declare the dependencies as constructor parameters and if the superclass also has … Read more
“Magically available interfaces” or global types is highly discouraged and should mostly be left to legacy. Also, you should not be using ambient declaration files (e.g. d.ts files) for code that you are writing. These are meant to stand-in the place of external non-typescript code (essentially filling in the typescript types into js code so … Read more
You need to import the map operator: import ‘rxjs/add/operator/map’ Or more generally: import ‘rxjs/Rx’; Notice: For versions of RxJS 6.x.x and above, you will have to use pipeable operators as shown in the code snippet below: import { map } from ‘rxjs/operators’; import { HttpClient } from ‘@angular/common/http’; // … export class MyComponent { constructor(private … Read more