JSFiddle - React, Tailwind, and code Playground

HTML

<table id="students" border="1">
    <thead>
        <tr>
            <th>Name</th>
            <th>Age</th>
            <th>Grade</th>
        </tr>
    </thead>
    <tbody>
        <tr class="student">
            <td>Oscar</td>
            <td>23</td>
            <td>16.5</td>        
        </tr>
        <tr class="student">
            <td>Antonio</td>
            <td>32</td>
            <td>14</td>        
        </tr>
        <tr class="student">
            <td>Jessica</td>
            <td>21</td>
            <td>19</td>        
        </tr>
    </tbody>
</table>

JavaScript

var data = $('table#students tbody tr').map(function(index) {
    var cols = $(this).find('td');
    return {
        id: index + 1,
        name: cols[0].innerHTML,
        age: (cols[1].innerHTML + '') * 1, // parse int
        grade: (cols[2].innerHTML + '') * 1 // parse int
    };
}).get();

console.log(data);