iam trying to set a variable as a keyname but as always iam just failing. (javascript newbie)

Here is my example object:

```
disk = {
    "id": {
        "type": "xxxx",
        "content": "xxxx"
    }
}

```

Later i want to output my content with disk[id].content. Now the question is how to set the key 'id' with an variable? (got a unique id with i try to get in there)

In the end it should read: (for example)
 disk = {
 "5546": {
 "type": "xxxx",
 "content": "xxxx"
 }
 }

Thanks a lot for your help!