ERROR TypeError: Cannot read properties of undefined (reading 'push') in child element in-CodePudding

I have this array in my child element

  @Input() listAnswer: any;

  changestyle(event)
  {
   let activeSpan = event.target;
   this.listAnswer.push(activeSpan.innerText.trim());
  }

passing this variable from parent component

<app-child [listAnswer]="listAnswer"></app-child>

but getting this error

ERROR TypeError: Cannot read properties of undefined (reading 'push')

the same code was working on main component.

Any suggestion Thanks

CodePudding user response：

You should initialized some value during the listAnswer input declaration on your component.ts. Like below:

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

CodePudding user response：

your listanswer needs to be declared as an array:

@Input listAnswer: any[];

and in your parent component also needs to have its listAnswer property be an array type.