Parent to child

 both this child calles in the parent i have challange that in child1 dropdown selection change i need to call api in child2 how to do it <app-newhire-header-details [parentData]="parentData" [formData]="combinedFormData.masterHeader" (formDataChange)="onFormDataReceived('masterHeader', $event)"></app-newhire-header-details> <app-personal-tab [formFields]="tabFormFields[2]" [tabKey]="2" [formData]="combinedFormData.personal" (formDataChange)="onFormDataReceived('personal', $event)" (nextTab)="nextTab()" (prevTab)="prevTab()"> </app-personal-tab>

For child-to-child communication, where a change in one child component triggers an action (like an API call) in a sibling child component, the standard Angular approach is for the parent component to act as a mediator

. A shared service is a more robust solution for complex scenarios or when components are not direct siblings. 

Solution 1: Parent as a mediator

This is the most straightforward and recommended approach for components that are direct siblings under the same parent.

1. Emit an event from the first child (app-newhire-header-details)
In newhire-header-details.component.ts, emit an event when the dropdown selection changes. 

typescript

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

@Component({ ... })
export class NewhireHeaderDetailsComponent {
  // Add a new @Output for the dropdown change
  @Output() dropdownChange = new EventEmitter<any>();

  onDropdownSelectionChange(value: any) {
    // This method is called by the dropdown's (change) or (selectionChange) event
    this.dropdownChange.emit(value);
  }
}

Use code with caution.

2. Listen to the event in the parent component
The parent component listens for the event from the first child. 

typescript

// parent.component.html
<app-newhire-header-details
  [parentData]="parentData"
  [formData]="combinedFormData.masterHeader"
  (formDataChange)="onFormDataReceived('masterHeader', $event)"
  (dropdownChange)="onHeaderDropdownChange($event)">  <!-- Listen for the dropdownChange event -->
</app-newhire-header-details>

<app-personal-tab
  [formFields]="tabFormFields[2]"
  [tabKey]="2"
  [formData]="combinedFormData.personal"
  [headerDropdownValue]="headerDropdownValue"  <!-- Pass the value to the second child -->
  (formDataChange)="onFormDataReceived('personal', $event)"
  (nextTab)="nextTab()"
  (prevTab)="prevTab()">
</app-personal-tab>

Use code with caution.

In parent.component.ts, implement the event handler and use it to update an input property on the second child.

typescript

// parent.component.ts
import { Component } from '@angular/core';

@Component({ ... })
export class ParentComponent {
  headerDropdownValue: any;

  onHeaderDropdownChange(selectedValue: any) {
    // Save the new value from the first child
    this.headerDropdownValue = selectedValue;
    // The second child will be notified of the change via its @Input()
  }

  // ... other methods
}

Use code with caution.

3. Watch for changes in the second child (app-personal-tab)
The second child needs to receive the value from the parent and take action when it changes.

typescript

import { Component, Input, OnChanges, SimpleChanges } from '@angular/core';
import { YourApiService } from './your-api.service'; // Assume you have an API service

@Component({ ... })
export class PersonalTabComponent implements OnChanges {
  // @Input to receive the value from the parent
  @Input() headerDropdownValue: any;

  constructor(private yourApiService: YourApiService) {}

  ngOnChanges(changes: SimpleChanges) {
    if (changes['headerDropdownValue']) {
      const selectedValue = changes['headerDropdownValue'].currentValue;
      if (selectedValue) {
        // Call your API based on the selected value
        this.callApi(selectedValue);
      }
    }
  }

  callApi(value: any) {
    // Logic to call your API based on the value
    this.yourApiService.getData(value).subscribe(
      (response) => console.log('API response for PersonalTab:', response),
      (error) => console.error('API error:', error)
    );
  }
}

Use code with caution.

---