Преобразование JSON в массив объектов JS

{
  "rows0": [
    {"id": 1, "lastName": "Snow", "firstName": "Jon", "age": 35},
    {"id": 2, "lastName": "Snow", "firstName": "Jon", "age": 35},
    {"id": 3, "lastName": "Snow", "firstName": "Jon", "age": 35},
    {"id": 4, "lastName": "Stark", "firstName": "Arya", "age": 16},
    {"id": 5, "lastName": "Targaryen", "firstName": "Daenerys", "age": 66},
    {"id": 6, "lastName": "Melisandre", "firstName": "Targaryen", "age": 150},
    {"id": 7, "lastName": "Clifford", "firstName": "Ferrara", "age": 44}
   ]
}

rows0: [
        {id: 1, lastName: 'Lannister', firstName: 'Jaime', age: 45},
        {id: 2, lastName: 'Lannister', firstName: 'Jaime', age: 45},
        {id: 3, lastName: 'Lannister', firstName: 'Jaime', age: 45},
        {id: 4, lastName: 'Stark', firstName: 'Arya', age: 16},
        {id: 5, lastName: 'Targaryen', firstName: 'Daenerys', age: 66},
        {id: 6, lastName: 'Melisandre', firstName: 'Targaryen', age: 150},
        {id: 7, lastName: 'Clifford', firstName: 'Ferrara', age: 44},
    ]

import * as React from 'react';
import { DataGrid } from '@material-ui/data-grid';
 
 
const rows =  fetch('http://localhost:3000/rows0');
const newData = JSON.parse(rows);
 
export let DataGridDemo0 = (props) => {
    return (
 
        <div style={{ height: 600, width: '99%', left: 0, top: 150}}>
            <DataGrid  
/* значения строк должны приходить из сервера*/
rows = {newData} 
/* значения колонок приходят из другого файла по пропсам*/ 
columns={props.columns} 
            pageSize={10} /* <= показывает максимум строк таблицы */ checkboxSelection />
        </div>
    );
}

const response = await fetch('localhost:3000/rows0');
const json = await response.json();
console.log(json);

fetch('localhost:3000/rows0').then((response) => response.json()).then((response) => console.log(response))