On a value change in the form in the child component I am trying to send an event to the parent component with the changed data from the form, but it keeps telling me that the

import { Component, OnInit, Input, Output, EventEmitter } from '@angular/core';

export class ClaimItemBoxesComponent implements OnInit {
 @Output() updatedBoxData = new EventEmitter();
 ngOnInit(): void {
    this.items.valueChanges.subscribe(this.onBoxFormChage);
 }
 onBoxFormChage(item) {
   this.updatedBoxData.emit(item) // Cannot read properties of undefined (reading 'updatedBoxData')
 }
}

If I emit the event inside ngOnInit outside the subscribe, it works like it should, but if inside the subscribe it does not.

CodePudding user response：

You have lost the context here, just bind it, or use lambda function:

ngOnInit(): void {
    this.items.valueChanges.subscribe(this.onBoxFormChage.bind(this));
}

or

ngOnInit(): void {
    this.items.valueChanges.subscribe((value) => this.onBoxFormChage(value));
}