Angular2 – should private variables be accessible in the template?

by

UPD

Since Angular 14, it is possible to bind protected components members in the template. This should partially address the concern of exposing internal state (which should only be accessible to the template) as the component’s public API.

No, you shouldn’t be using private variables in your templates.

While I like the drewmoore’s answer and see perfect conceptual logic in it, implementationwise it’s wrong. Templates do not exist within component classes, but outside of them. Take a look at this repo for the proof.

The only reason why it works is because TypeScript’s private keyword doesn’t really make member private. Just-in-Time compilation happens in a browser at runtime and JS doesn’t have any concept of private members (yet?). Credit goes to Sander Elias for putting me on the right track.

With ngc and Ahead-of-Time compilation, you’ll get errors if you try accessing private members of the component from template. Clone demonstration repo, change MyComponent members’ visibility to private and you will get compilation errors, when running ngc. Here is also answer specific for Ahead-of-Time compilation.

More Related Contents:

  1. *ngFor running an infinite loop in angular2
  2. Angular 2 custom form input
  3. How to get query params from url in Angular 2?
  4. How to inject Document in service?
  5. Angular 2 Show and Hide an element
  6. WARNING: sanitizing unsafe style value url
  7. Angular 2: Convert Observable to Promise
  8. Angular 2 Scroll to top on Route Change
  9. Angular2: How to load data before rendering the component?
  10. How to prepare release version with SystemJS and Gulp?
  11. Angular2 canActivate() calling async function
  12. How to display json object using *ngFor
  13. Angular no provider for NameService
  14. Angular 2 Read More Directive
  15. Angular2 – Share data between components using services
  16. vs
  17. Accessing a property in a parent Component
  18. TypeScript error in Angular2 code: Cannot find name ‘module’
  19. Angular 2 Dynamically insert a component into a specific DOM node without using ViewContainerRef
  20. Visual Studio Code Automatic Imports
  21. Generate dynamic css based on variables angular
  22. Get route query params
  23. RxJs get value from observable
  24. How to create an Observable from static data similar to http one in Angular?
  25. RxJs Array of Observable to Observable of Array
  26. Import gapi.auth2 in angular 2 typescript
  27. Angular 2 disable sanitize
  28. What exactly $event object do in Angular 2?
  29. How to deal with http status codes other than 200 in Angular 2
  30. Access Meta-Annotation inside Class (TypeScript)

Leave a Comment