How do you read a json parsed PDO error message?

From an Ajax function i’m running a php function that does a simple insert to a mysql table.

If it has no issues i just return a 1 and if it has an error it is caught by an exception and returns a json_encode($ex). Since the ajax function has a dataType of “json” it’s all good, except i get this in my answer variable:

    {
      "errorInfo": [
        "23000",
        1062,
        "Duplicate entry 'a' for key 'usuarios.usuario'"
      ]
    }

And it looks good but if i try something like console.log(answer["errorInfo][1]); to try to get just the code error i get some undefined errors and whatnot.

How can i access, individually, those 3 indexes inside of the errorInfo key?