Question

For example, I have:

var Data = [
  { id_list: 1, name: 'Nick', token: '312312' },
  { id_list: 2, name: 'John', token: '123123' },
]

Then, I want to sort/reverse this object by name, for example. And then I want to get something like this:

var Data = [
  { id_list: 2, name: 'John', token: '123123' },
  { id_list: 1, name: 'Nick', token: '312312' },
]

And now I want to know the index of the object with property name='John' to get the value of the property token.

How do I solve the problem?

Answer 1

As the other answers suggest, looping through the array is probably the best way. But I would put it in its own function, and make it a little more abstract:

function findWithAttr(array, attr, value) {
    for(var i = 0; i < array.length; i += 1) {
        if(array[i][attr] === value) {
            return i;
        }
    }
    return -1;
}

var Data = [
    {id_list: 2, name: 'John', token: '123123'},
    {id_list: 1, name: 'Nick', token: '312312'}
];

With this, not only can you find which one contains ‘John’, but you can find which contains the token ‘312312’:

findWithAttr(Data, 'name', 'John'); // returns 0
findWithAttr(Data, 'token', '312312'); // returns 1
findWithAttr(Data, 'id_list', '10'); // returns -1

The function returns -1 when not found, so it follows the same construct as Array.prototype.indexOf().