# angular.service.$updateView

Work in Progress This page is currently being revised. It might be incomplete or contain inaccuracies.

## Description

Calling `$updateView` enqueues the eventual update of the view. (Update the DOM to reflect the model). The update is eventual, since there are often multiple updates to the model which may be deferred. The default update delayed is 25 ms. This means that the view lags the model by that time. (25ms is small enough that it is perceived as instantaneous by the user). The delay can be adjusted by setting the delay property of the service.

    angular.service('$updateView').delay = 10

The delay is there so that multiple updates to the model which occur sufficiently close together can be merged into a single update.

You don't usually call '$updateView' directly since angular does it for you in most cases, but there are some cases when you need to call it.

- `$updateView()` called automatically by angular:
  - Your Application Controllers: Your controller code is called by angular and hence angular is aware that you may have changed the model.
  - Your Services: Your service is usually called by your controller code, hence same rules apply.
- May need to call `$updateView()` manually:
  - Widgets / Directives: If you listen to any DOM events or events on any third party libraries, then angular is not aware that you may have changed state state of the model, and hence you need to call '$updateView()' manually.
  - 'setTimeout'/'XHR': If you call 'setTimeout' (instead of `angular.service.$defer`) or 'XHR' (instead of `angular.service.$xhr`) then you may be changing the model without angular knowledge and you may need to call '$updateView()' directly.

NOTE: if you wish to update the view immediately (without delay), you can do so by calling `angular.scope.$eval` at any time from your code:

    scope.$root.$eval()

In unit-test mode the update is instantaneous and synchronous to simplify writing tests.

## Dependencies

- `$browser`