Questions tagged [angular2-changedetection]
473 questions
14
votes
1 answer
behaviourSubject in angular2 , how it works and how to use it
I am trying to build a shared service as follow
import {Injectable,EventEmitter} from 'angular2/core';
import {Subject} from 'rxjs/Subject';
import {BehaviorSubject} from 'rxjs/subject/BehaviorSubject';
@Injectable()
export class SearchService…
Ironsun
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13
votes
1 answer
Angular 2: ChangeDetection and mousemove event
I have an Angular 2 Component with many children.
Because of performance issues, I wanted to check how often the ChangeDetection checks my child-components. So I logged the ngAfterViewChecked-callback of one of my child-components.
I realized that…
ant45de
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13
votes
3 answers
Detect change in child component's variable triggered by parent angular 2
I have 2 files. app.ts and Child.ts
I am sending a variable from app to child and I want to detect any change in the variable and show data accordingly. I am not able to detect changes in a variable.
Any Help? I have attached Plunker Link and I have…
amansoni211
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13
votes
2 answers
How to check if Change Detection was triggered on a component
In my app I want to set manual change detection. For this I set the ChangeDetectionStrategry to OnPush and whenever a change occurs in a component I manually run change detection using detectChanges.
If I set ChangeDetectionStrategy to OnPush on a…
Naveed Ahmed
- 10,048
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12
votes
1 answer
What does Angular Ivy specifically allow us to do in regards to manual change detection?
This article mentions that
Ivy opens a few possibilities for the future though. It should now be possible to run an application without zone.js, and to semi-manually handle change detection (a bit like you would with React). These APIs already…
Maxime Dupré
- 5,319
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12
votes
1 answer
Angular OnPush: how do I force changes to be detected from outside?
I have a scenario where I have two components sitting alongside each other, ComponentA and ComponentB. They both use a service Service.
ComponentB contains a button which will make a property in Service, Service.counter, go up by 1.
ComponentA…
Bart van den Burg
- 2,166
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12
votes
2 answers
Angular 5.0 change detection strategy VS React's change detection strategy
I understood how change detection works in Angular 5.0.
Can some one help me to understand how the same works in React and how much it was different from Angular's ?
kalki
- 465
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11
votes
3 answers
Expression has changed after it was checked - MatDialog Angular 6
I have read several answers, and I have tried many but I can't seem to get this to work. In my angular 6 app, I try to open a MatDialog but I receive this error:
ERROR Error:
ExpressionChangedAfterItHasBeenCheckedError:
Expression has changed…
Michael
- 3,093
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- 83
10
votes
1 answer
Change Detection works intermittently when receiving data from Electron Container IPC Channel
I have an application that is listening for incoming data from an IPC Renderer Channel. Here is my setup:
container that sends data to angular app (mainWindow):
mainWindow.loadURL('http://www.myangularapp.com') //where the angular app lives (example…
Kode_12
- 4,506
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10
votes
2 answers
@HostListener cause change detection triggers too many times when I'm listening for outside click
I have next template of root component, that draws 9 tiles:
Artem
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10
votes
4 answers
Would you recommend ChangeDetectionStrategy.OnPush as default changeDetection in Angular 2?
Would it be a reasonable convention within an Angular-2 project to always use
changeDetection: ChangeDetectionStrategy.OnPush
within a component's decorator? Except when there are clear reasons to use the default-strategy?
Martin Cremer
- 5,191
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10
votes
2 answers
How to reuse the elements of ngFor even if the list reference changes?
I have an Angular 2 component that uses *ngFor to render a nested array of numbers.
@Component({
selector: 'app',
template: `
…
danijar
- 32,406
- 45
- 166
- 297
9
votes
2 answers
Angular: Change in Pipe not detected
I have this pipe which multiplies the input value by an other value retrieved from a service:
@Pipe({
name: 'multiply'
})
export class MultiplyPipe implements PipeTransform {
constructor(private service: StateService) { }
…
Jeanluca Scaljeri
- 26,343
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9
votes
2 answers
Angular - Is binding a component method to DOM target property a wrong practice?
Say, I have a component which is used as following:
After reading data-binding related parts from https://angular.io/guide/template-syntax, it seem like the…
Uthman
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9
votes
1 answer
Angular ngDoCheck() gets called even with ChangeDetectionStrategy.OnPush
Lets say i have a component structure like this:
AppComponent
HeaderComponent
ContentComponent
TodosComponent
TodoComponent
If I set HeaderComponent's changeDetection to ChangeDetectionStrategy.OnPush and change…
Mick
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