CODE EXAMPLE FOR JAVASCRIPT

js search in object

function filter(array, value, key) {
    return array.filter(key
        ? a => a[key] === value
        : a => Object.keys(a).some(k => a[k] === value)
    );
}

var a = [{ name: 'xyz', grade: 'x' }, { name: 'yaya', grade: 'x' }, { name: 'x', frade: 'd' }, { name: 'a', grade: 'b' }];


console.log(filter(a, 'x'));
console.log(filter(a, 'x', 'name'));