How to append an array (hardcoded way) to a json array with append function

Question

I work on json path and I study the differents functions of this query language. I tried to use the 'append' function to see how far we can go with it and here's my case :

{
    "book": [{
            "category": "reference"
        }, {
            "category": "fiction"
        }
    ],
    "rndarr": ["foo", 10]
}

Here's my goal : I want to retrieve all book array and add to this array another array, so I tried this : $.book.append(["foo",10]) and it returned me this :

[
    {
        "category": "reference"
    },
    {
        "category": "fiction"
    },
    "foo"
]

As you can see the 10 completly disappear, and here's another weird behavior : when I run this : $.book.append([10]) it returns this :

[
    {
        "category": "reference"
    },
    {
        "category": "fiction"
    },
    "10]"
]

To makes things clear my expected output should normally be this (for the first problem) :

[
    {
        "category": "reference"
    },
    {
        "category": "fiction"
    },
    ["foo", 10]
]

After all of this I tried to make a trick. I tried to call an array that already exist rndarr and it works : $.book.append($.rndarr) this return the expected output

[
    {
        "category": "reference"
    },
    {
        "category": "fiction"
    },
    [
        "foo",
        10
    ]
]

So my question is : Is it possible to write in an hard-coded way a jsonpath that use append function with an array ?