change key/values of an object

If I have a result like this:

result =  [

    { '0': 'grade', A: 'name', b1: 'number' },
    { '1': 'grade', B: 'name', b2: 'number' },
    { '2': 'grade', C: 'name', b3: 'number' }
];

How can I produce :

result =  [

    { A: '0', b1: '0' },
    { B: '1', b2: '1' },
    { C: '2', b3: '1' }
];

I want to pass the analogous grade instead of name and number.