libbson can produce a non-portable Legacy Extended JSON format.

WARNING:

Use of the Legacy Extended JSON format is discouraged. Prefer Canonical Extended JSON or Relaxed Extended JSON for portability.

MongoDB Extended JSON (v2) describes the preferred Relaxed Extended JSON format and Canonical Extended Formats

libbson's Legacy Extended JSON format matches Relaxed Extended JSON with the following exceptions. Notation is borrowed from MongoDB Extended JSON (v2):

Type	Legacy Extended JSON
Binary	0.0 3.5 { "$binary": "<payload>", "$type": "<t>" } 168u 168u
Date	0.0 3.5 { "$date" : "<millis>" } 168u 168u
Regular Expression	0.0 3.5 { "$regex" : "<regexPattern>", "$options" : "<options>" } 168u 168u
DBPointer (deprecated)	0.0 3.5 { "$ref" : "<collection namespace>", "$id" : "<ObjectId bytes>" } 168u 168u
Symbol (deprecated)	0.0 3.5 "<string>" 168u 168u
Double infinity	infinity or inf without quotes. Implementation defined. Produces invalid JSON.
Double NaN	nan or nan(n-char-sequence). Implementation defined. Produces invalid JSON.

AUTHOR

MongoDB, Inc

COPYRIGHT

2009-present, MongoDB, Inc.