ejson

EJSON is an extension of JSON to support more types. It supports all JSON-safe
types, as well as:

- Date - JavaScript Date
- Binary - JavaScript Uint8Array or the
result of EJSON.newBinary
- User-defined types - see EJSON.addType

All EJSON serializations are also valid JSON. For example an object with a date
and a binary buffer would be serialized in EJSON as:

{
"d": {"$date": 1358205756553},
"b": {"$binary": "c3VyZS4="}
}

For more details, see the EJSON section of the Meteor docs.