DoCheck

What it does

Lifecycle hook that is called when Angular dirty checks a directive.

How to use

.

@Component({selector: 'my-cmp', template: `...`})
class MyComponent implements DoCheck {
  ngDoCheck() {
    // ...
  }
}

Class Description

ngDoCheck gets called to check the changes in the directives in addition to the default algorithm. The default change detection algorithm looks for differences by comparing bound-property values by reference across change detection runs.

Note that a directive typically should not use both DoCheck and OnChanges to respond to changes on the same input, as ngOnChanges will continue to be called when the default change detector detects changes.

See KeyValueDiffers and IterableDiffers for implementing custom dirty checking for collections.

See Lifecycle Hooks Guide.