Type an array of type any[] at angular 6

Question

I need to type an object, not to receive any[] in agular 6. Well, no get, I get this from the API:

{
    "error": false,
    "itens": [
        [
            {
                "operatorId": "819ee9cc-70b6-44dc-b9e8-afff8705142c",
                "name": "Vera Silva"
            },
            {
                "operatorId": "ccad3b40-c227-425e-b3b1-feedf6cfac2e",
                "name": "Catarina Silva"
            },
            {
                "operatorId": "68781a7b-ac4c-4a85-9f93-36dc5d65d1af",
                "name": "José da Silva"
            }
        ]
    ],
    "message": ""
}

In my Component I re-read so(getAll)

import { Component, OnInit } from '@angular/core';
import { Operator } from '../operator';
import { OperatorService } from '../operator.service';

export interface getOperator{
  Id: string;
  Name: string;
}

@Component({
  selector: 'app-operators',
  templateUrl: './operators.component.html',
  styleUrls: ['./operators.component.css'],
  providers: [OperatorService]
})

export class OperatorsComponent implements OnInit {

   displayedColumns: string[] = ['codigo', 'nome'];

    public message: string;
    public dataSource: any[];

    constructor
    (
        private _operService: OperatorService
    ) 
    {
        //this.message = 'Hello from HomeComponent constructor';
    }

  ngOnInit() {

  this._operService
      .getAll<any[]>()
      .subscribe((data: any[]) => {
        debugger;
        this.dataSource = data.itens
      });
  }
}

Notice that my datasource receives an array of type any[]. This is making my mat-table in my html is not populated. My html

div>
  <table mat-table [dataSource] = "dataSource" class="mat-elevation-z8">

     <ng-container matColumnDef="codigo">
       <th mat-header-cell *matHeaderCellDef> Codigo </th>
       <td mat-cell *matCellDef="let oper"> {{oper.Id}} </td>
    </ng-container>

    <ng-container matColumnDef="nome">
      <th mat-header-cell *matHeaderCellDef> Nome </th>
      <td mat-cell *matCellDef="let oper"> {{oper.Name}} </td>
    </ng-container>

    <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
    <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
    </table>
</div>

the idea would be to type instead of pass a any[], but don’t know how I do it? I would create on the Angular side a class like this: error, items, message? and put in Any’s place, like:

export class Item{
error: boolean;
itens: array de alguma coisa;
message: string;
}

that would be it?

EDIT1

Following the guidance of colleague Gustavo Santos, I did the following:

export class Operation{
    error: boolean;
    itens: Array<Itens[]>;
    message: string;
}

export class Itens{
    objectId: string;
    name: string;
}

but when it was installed in Component, it says [ts] Property 'items' does not exist on type 'Operation[]', right here:

debugger;
this.dataSource = data.itens;

My Component is like this:

import { Component, OnInit } from '@angular/core';
import { Operator } from '../operator';
import { OperatorService } from '../operator.service';
import { Operation } from '../model/operators/operations';

export interface getOperator{
  Id: string;
  Name: string;
}

@Component({
  selector: 'app-operators',
  templateUrl: './operators.component.html',
  styleUrls: ['./operators.component.css'],
  providers: [OperatorService]
})

export class OperatorsComponent implements OnInit {

   displayedColumns: string[] = ['codigo', 'nome'];

    public message: string;
    public dataSource: Operation[];

    constructor
    (
        private _operService: OperatorService
    ) 
    {        
    }

  ngOnInit() {

  this._operService
      .getAll<Operation[]>()
      .subscribe((data: Operation[]) => {
        debugger;
        this.dataSource = data.itens;
      });
  }
}

Answer 1

The ideal is to always type, you are on the right track, if you follow your JSON, you have to have these classes:

export class Operation {
    error:   boolean;
    items:   Array<Item[]>;
    message: string;
}

export class Item {
    operatorId: string;
    name:       string;
}

And when you give this. _operService.getAll(), replace it with:

this._operService.getAll<Operation>()