How check for ObjectId? about runtypes

[yuhr]

I'm not familiar with MongoDB, but as far as I can tell according to the documentation, it's binary format that you need to parse by yourself, as runtypes doesn't understand binary data.

I don't know what you exactly mean by “check”, but if you want to ensure that a given 12-byte data is truly meant to be ObjectId, the only option would be to ask the sender of the data to wrap the bytes by some tag, like { tag: "ObjectId", payload: "507f1f77bcf86cd799439011" } and test it by Record({ tag: Literal("ObjectId"), payload: String }), since the format is not self-descriptive i.e. it does not contain some kind of “magic bytes” to identify itself is an ObjectId.

[205g0]

Thanks, just checking if instanceof ObjectId would be enough, also I would like to keep it like it is and not transformed to a string

[yuhr]

Oh sorry, then InstanceOf runtype is exactly what you want. Going to add to the documentation. Thanks!