A simple Writable stream that executes a batch operation on a given levelDB
instance. Perfect to use in conjunction with batch-stream to
batch up your array size for you and concurrent-writable for
tweaking the batch execution concurrency level.
var level = require('level-hyper');
var through = require('through2');
var LevelBatch = require('level-batch-stream');
var BatchStream = require('batch-stream');
var parallel = require('concurrent-writable');
var db = level('new.db', { valueEncoding: 'json' });
source
//
// Turn source data into what levelup expects in batches
//
.pipe(through(function (data, enc, cb) {
data = { type: 'put', key: data.id, value: data };
cb(null, data);
}))
//
// Will batch up 100 objects an send an array down the chain
//
.pipe(new BatchStream({ size: 100 }))
//
// Will batch the arrays it receives into the level instance
// doing up to a max of 10 concurrently
//
.pipe(parallel(new LevelBatch(db), 10))