Translate table in pure js

Try this in your loop to reference each cell and assign from your 2d array:

table.rows[i].cells[j].innerHTML = array[i][j];

Loop over the array instead and use document.createElement to create rows and cells to append to the tbody.

const tbody = document.querySelector('table > tbody');
var array = [
      ["a1", "b1", "c1"],
      ["a2", "b1", "c1"],
      ["a3", "b1", "c1"],
      ["a4", "b1", "c1"],
      ["a5", "b1", "c1"],
      ["a6", "b1", "c1"],
      ["a7", "b1", "c1"],
    ];
for (var i = 0; i < array.length; i++) {
  const row = document.createElement('tr');
  for (var j = 0; j < array[i].length; j++) {
    const cell = document.createElement('td');
    cell.textContent = array[i][j];
    row.appendChild(cell);
  }
  tbody.appendChild(row);
}
<link href="https://getbootstrap.com/docs/4.0/dist/css/bootstrap.min.css" rel="stylesheet"/>
<table class="table table-striped" id="TabelPret">
  <thead>
    <tr>
      <th scope="col">id</th>
      <th scope="col">service</th>
      <th scope="col">price(Euro)</th>
    </tr>
  </thead>
  <tbody>                            
  </tbody>
</table>