Awesome
level-sublevel-stream
Find all the sublevels of a given database, not requiring them to be in memory already.
Motivation
Most modules currently inspect db.sublevels
to find out all the sublevels of
a db, but this approach only works when the sublevel has been used since the
app started up, otherwise there's no in memory representation of the sublevel,
it's only in the db.
This module efficiently queries the db to find all the sublevels.
Example
Insert some data into different sublevels, then close and reopen the db, and
finally use level-sublevel-stream
to find all the sublevels.
var level = require('level');
var sub = require('level-sublevel');
var subStream = require('level-sublevel-stream');
var db = sub(level(__dirname + '/db'));
db.batch([
{ type: 'put', prefix: db.sublevel('a'), key: 'aa', value: 'aa' },
{ type: 'put', prefix: db.sublevel('a'), key: 'ab', value: 'ab' },
{ type: 'put', prefix: db.sublevel('b'), key: 'ba', value: 'ba' },
{ type: 'put', prefix: db.sublevel('b'), key: 'bb', value: 'bb' }
], function(err) {
db.close(function(err) {
db = sub(level(__dirname + '/db'));
subStream(db).on('data', console.log);
});
});
$ node example.js
a
b
API
subStream(db[, opts])
Create a readable stream from all sublevels in db
. db
can be an
instance of levelup or a sublevel itself.
Possible options are:
reverse
: If true, emit sublevels in reverse lexicographic ordergt
: Only emit sublevels whose name sort>
that valuegte
: Only emit sublevels whose name sort>=
that valuelt
: Only emit sublevels whose name sort<
that valuelte
: Only emit sublevels whose name sort<=
that value
Installation
With npm do:
npm install level-sublevel-stream
License
(MIT)
Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.