Error: The type of key must be string or number but object is thrown when decoding a object with null as key

[ZumiKua]

const b = Buffer.from("gaRkYXRhgaRzaG9wgqdhbGNoZW15gqltYXhfY291bnRGqmV4ZWNfY291bnQAr3JlY292ZXJfc3RhbWluYYbAAaVjb3VudB6pbWF4X2NvdW50HqpleGVjX2NvdW50AKhyZWNvdmVyeXikY29zdCg=", "base64");
msgpack5 = require("msgpack5");
console.log(msgpack5().decode(b));
msgpack = require("@msgpack/msgpack");
console.log(msgpack.decode(b));

with the above code, msgpack5 can successfully decode the content but msgpack throws Error: The type of key must be string or number but object

The version of msgpack I'm using is 2.4.1, Node version is v10.14.2

The json version of the message is:

{
    "data":{
        "shop":{
            "alchemy":{
                "max_count":70,
                "exec_count":0
            },
            "recover_stamina":{
                "":1,
                "count":30,
                "max_count":30,
                "exec_count":0,
                "recovery":120,
                "cost":40
            }
        }
    }
}

It seems that this is caused by an empty string key.

According to this link, an empty string is a valid json key, I think this applied to Msgpack as well?

[ZumiKua]

Sorry, my bad, the actual message is something like

{ shop:
   { alchemy: { max_count: 70, exec_count: 0 },
     recover_stamina:
      { null: 1,
        count: 30,
        max_count: 30,
        exec_count: 0,
        recovery: 120,
        cost: 40 } } }

the key here is null, which is not supported as the exception stated.