You need to import the Observable class this way to be able to use the interval method: import {Observable} from ‘rxjs/Rx’; or import {Observable} from ‘rxjs/Observable’; import ‘rxjs/add/observable/interval’;
If you are using VSCode, you can use CTRL + SHIFT + P to open the command palette and search for “Restart” or “Reload”, you should have “Restart TS Server” and “Reload Project”, both work well.
A few things are going on here. The first (minor) issue is that, with your Student interface, the compiler will not treat checking the isValid property as a type guard: const s = students[Math.random() < 0.5 ? 0 : 1]; if (s.isValid) { foo([s]); // error! // ~ // Type ‘Student’ is not assignable to … Read more
following the yup guide here you should change your code as follows: import { object, SchemaOf, string } from ‘yup’; interface BaseBootstrapSchema { APPLICATION_NAME: string; LOG_PATH: string; } const bootstrapValidationSchema: SchemaOf<BaseBootstrapSchema> = object({ LOG_PATH: string().required(“The ‘LOG_PATH’ ENV variable is required”), APPLICATION_NAME: string().required(“The ‘APPLICATION_NAME’ ENV variable is required”), }); module.exports = (schema: SchemaOf<BaseBootstrapSchema>) => new Promise((resolve, … Read more
I could be wrong because I’ve only done this with of loops, but you should be able to enforce a type definition on the collection (right side) which informs the typing on the item. For example: for (role in roles as Roles[]) This should make each element of type Roles.
You’ll need to use a mapped tuple type, which is supported in TypeScript 3.1. You can make a mapped type that has properties 0, 1, 2 and length of the correct types, like this: class Maybe<T> {} type MaybeTuple = [Maybe<string>, Maybe<number>, Maybe<boolean>]; type MaybeType<T> = T extends Maybe<infer MaybeType> ? MaybeType : never; type … Read more
Vuex is perfectly compatible with typescript using these vuex imports: import {GetterTree, MutationTree, ActionTree} from “vuex” The example below shows the easiest and most complete way to use vuex in typescript. Principal store file: import Vue from ‘vue’ import Vuex from ‘vuex’ import { GetterTree, MutationTree, ActionTree } from “vuex” import MySubModule from ‘@/store/submodule’ Vue.use(Vuex) … Read more
I banged my head on this for a few hours, but the solution seems obvious in retrospect. First I present the solution, then I compare it to prior approaches. (Tested in Typescript 2.6.2.) // WORKING SOLUTION: union of types with type checks class MustBeThis { method1() { } } class OrThis { method2() { } … Read more
Similar to Colins answer, but coming at it from the opposite direction. If you have an existing interface/type you need to pick apart you can use indexes: // Existing type type Tenant = { id:string; description:string; name:string; approvedUsers: Array<{ id:string; alias:string; }> } // Pick it apart type TenantManagePageQueryTenant = Pick<Tenant, ‘id’ | ‘description’ | … Read more
Yes you should remove async. You should not force to use async to the class that implements it. There are other ways to return a Promise, not just async. Edit: Since it is not clear for some people why the async is not important. Here a couple of ways to return a promise: async function … Read more