Is key-value pair available in Typescript?
Is key-value pair available in Typescript? Yes. Called an index signature: Here keys are string and values are number. More You can use an es6 Map for proper dictionaries, polyfilled by core-js.
typescript
Implement session storage in an Angular 8 application
For saving values while refreshing the page, you can use the localStorage or the sessionStorage for that. There is no external library or import necessary. It should work out of the box in most of the browsers. For saving: For loading: You can check this in Chrome using the dev tools.
Angular 2 Checkbox Two Way Data Binding
You can remove .selected from saveUsername in your checkbox input since saveUsername is a boolean. Instead of [(ngModel)] use [checked]=”saveUsername” (change)=”saveUsername = !saveUsername” Edit: Correct Solution: Update: Like @newman noticed when ngModel is used in a form it won’t work. However, you should use [ngModelOptions] attribute like (tested in Angular 7): I also created an example at Stackblitz: https://stackblitz.com/edit/angular-abelrm
How to update TypeScript to latest version with npm?
Try npm install -g typescript@latest. You can also use npm update instead of install, without the latest modifier.
Angular 2 : No NgModule metadata found
The problem is in your main.ts file. You are trying to bootstrap App, which is not a real module. Delete these two lines and replace with the following line: and it will fix your error.
How to implement sleep function in TypeScript?
You have to wait for TypeScript 2.0 with async/await for ES5 support as it now supported only for TS to ES6 compilation. You would be able to create delay function with async: And call it BTW, you can await on Promise directly: Please note, that you can use await only inside async function. If you can’t (let’s say you are building nodejs application), just … Read more
Constructor overload in TypeScript
TypeScript allows you to declare overloads but you can only have one implementation and that implementation must have a signature that is compatible with all overloads. In your example, this can easily be done with an optional parameter as in, or two overloads with a more general constructor as in, See in Playground
Can’t perform a React state update on an unmounted component
Here is a React Hooks specific solution for Error Warning: Can’t perform a React state update on an unmounted component. Solution You can declare let isMounted = true inside useEffect, which will be changed in the cleanup callback, as soon as the component is unmounted. Before state updates, you now check this variable conditionally: Show code snippet Extension: Custom useAsync Hook We can … Read more
TypeError: Class extends value undefined is not a function or null
I was having the same issue. It turns out I was circularly importing classes, which is apparently a limitation. (See these GitHub issues: #20361, #4149, #10712) Note that it seems that the circular reference is also limited between files, not simply types. See this other answer
What is the difference between .ts and .tsx extensions. Both are used as extensions for typescript files in react. So where should we use them?
Use .ts for pure TypeScript files. Use .tsx for files which contain JSX. For example, a React component would be .tsx, but a file containing helper functions would be .ts.