Ace tern editor. Make own autocomplete properties for unknown value

[goldpvlv]

Hi, i have default.json file with properties. Example,

{
    "!name": "test",
         "Commit": {
             "!doc": "test",
             "!type": "fn(connectionName: string, k: string) -> object"
                "default": {
                "!doc": "test",
                "z": {
                     "!doc": "test"
                     },
                "p": {
                      "!doc": "test"
                     }
        }
}

In redactor

var t = 'string';
Commit.t.

and i need that autocomplete with 'default' properties appears after "t". So, if "Commit" dont have that property (in this case "t"), then properties 'z' and 'p' appear.
how i can did it?
thanks