How to pass data from child to parent?

I need to pass one variable, that is inside my child component, to parent page. This variable that I am trying to pass, is the array result of Barcode Scanner.

And I need to pass it to parent to send to API.

childComponent.ts

this.consultList;

parentComponent.ts

export class ParentComponent implements OnInit {

@Input() consultList: any[] = [];

testCall() {
console.log('Test Consult: ', this.consultList; 
}

Answer

Here is an example stackblitz project to test parent-child data transfer, using @Input() and @Output()mechanism

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

@Component({
  selector: 'child',
  template: `
    <h1>Hello {{ name }}! This is child component</h1>
    <button (click)="sendEventToParent()">Send data to parent</button>
  `,
  styles: [
    `
      h1 {
        font-family: Lato;
      }
    `
  ]
})
export class ChildComponent {
  @Input() name: string;
  @Output() eventFromChild: EventEmitter<string> = new EventEmitter();

  sendEventToParent(): void {
    this.eventFromChild.emit('data from child');
  }
}

here is the parent component html called child

<child name="{{ name }}" (eventFromChild)="onEvent($event)"></child>

<h1>This is parent component</h1>
<p>{{dataFromChild}}</p>

and event bindin like that

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

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  name = 'Angular ' + VERSION.major;
  dataFromChild = '';

  onEvent(event): void {
    this.dataFromChild = event;
  }
}