DrPizza points out that we are presently unable to roundtrip single values through our javascript BSON library:

• BSON.deserialize(BSON.serialize([])) yields "{}"
• BSON.deserialize(BSON.serialize([1, 2, 3])) yields " {0: 1, 1: 2, 2: 3}

  "

• BSON.deserialize(BSON.serialize(1)) yields "{}"
• and so on..

We should consider two approaches, and perhaps a marriage of the two:

• Explicitly disallow non-object inputs
• Provide a mechanism to roundtrip single values (perhaps wrapping the value in some reserved key like $$single$$, we do something similar in Swift)