How to trigger event when array item value changes

Question

I have objects coming in to my array. When change the value of the objects, let's say id. I need an event or something like that to be triggered.

This is how I add my objects:

 const entry= new CompletableEntry('models.Address.addressLine2._TITLE');
 this.globalLoadingScreenService.addTask(entry);
 task.updateID(3);

Updating the ID won't trigger anything but I have a function that needs to be triggered when a value changes. The function checks if all the objects have status of complete and if yes it will delete all items in array.

I know one way to get this would be by adding them trough my service but I kind of require solution that won't update the task status trough service.

Nischaya Sharma · Accepted Answer · 2021-06-17 12:10:51Z

2

You can either create a custom observable array to which you can subscribe to. This might help.

What I came up with is you can create a BehaviourSubject and subscribe to it.

import { BehaviorSubject } from 'rxjs';
arrayChanged = new BehaviourSubject(false);

//The function where actually the array is updating
fun update() {
    ...
    this.arrayChanged.next(!this.arrayChanged.value);
}

// Then to listen to the array changes.

this.arrayChanged.subscribe( value => {
    //The function you want to run goes here.
    // this block runs everytime there is some change in the behaviour subject
})

answered Jun 17, 2021 at 12:10

Nischaya Sharma

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1 Comment

C0mpl3x Over a year ago

I used your answer but in a different way. When a status is changed a created a field completed which is a BehaviourSubject, so when I add a new entry a subscribe to it and when it changes I get a trigger. Also it would work if I used the status as a BehaviourSubject. I'll modify your answer and give and select it as the right answer.

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