delete a range

[Raynos]

Having a function for

db.del({
    start: "a"
    , end: "b"
})

Would be useful.

Use-case here is to have mechanism to purge old data mainly

db.del({
    start: "name:"
    , end: "name:someTs"
})

[Raynos]

This should probably be a user module

[rvagg]

I'm going to reopen this because it's going to be way more efficient to do it directly against leveldb and not have to go back and forth from V8.

[Raynos]

leveldb has a direct api for this?

[rvagg]

no, but it could be done directly via an iterator, totally async

[juliangruber]

That's the way I went with leveled also, do all the iterator stuff directly in C

[rvagg]

this needs to be done in LevelDOWN, I'd like almost identical options to those which you provide to readStream(), it's just a matter of naming. I'm not sure overloading del() is a good idea, something like delRange(), rangeDel(), delBatch() (confusing perhaps cause it wouldn't atomic in the same way batch() is). Or maybe I'm just viewing this as an implementer rather than an API user? If you think overloading del() is a good idea can you provide some code examples of how that would be done nicely without being confusing & magically implicit (always prefer explicit).

[dcousens]

Is the best way to do this using:

db.batch()
   .del(...)
   .del(...)
   .del(...)
   .del(...)
   .del(...)
   ...

?
Or is there an iterator variant without crossing the V8 boundary (ala level-delete-range)

[fergiemcdowall]

Range delete would be nice functionality, and it would also provide some symmetry with gt/gte/lt/lte in .createReadStream().

Thinking out loud here: it would be great if you could read ranges or specified keys. For example:

db.createReadStream({keys: ['id1'', 'id3', 'id16']})

db.del({keys: ['id1'', 'id3', 'id16']})

db.del({gte: 'id2', lte: 'id5'})