It's impossible to have legit one char key without it having the chance of being changed to another value

[JimZeeKing]

With this object as source, "G" will get changed to "config" after unpacking because G will be the key used to replace "config" key .
var tt = { config:{ positions:{ F:200, G:200, }, A:{ test:123, test2:"ABC" } } }

results in (after unpacking)

var tt = { config:{ positions:{ F:200, config:200, }, A:{ test:123, test2:"ABC" } } }