errorCallback in Lightning Webcomponent

It is called when the component throws an error in one of it’s call back methods.
Error is a JavaScript native error object, stack argument is a string.
childComponent.html
<template>
   childcomponent
</template>
childComponent.js
import { LightningElement} from 'lwc';
export default class ChildComponent extends LightningElement {
    constructor(){
        super();
        console.log('Yes I am in child constructor');
        throw 'This is the custom error message from child component';
    }
    errorCallback(error,stack){
        alert('error'+error);
        alert('stack'+stack);
    }
}
parentComponent.html
<template>
    <c-child-component>
    </c-child-component>    
</template>
parentComponent.js
import { LightningElement,api } from 'lwc';
export default class ParentComponent7 extends LightningElement {
    constructor(){
        super();
        console.log('Yes I am in parent constructor');
    }
    errorCallback(error,stack){
        alert('error'+error);
        alert('stack'+stack);
    }
}
LightningApplication
<aura:application>
	<c:parentComponent>
	</c:parentComponent>
</aura:application>
output:
errorThis is the custom error message from child component
stack<c-parent-component> <c-child-component>