lots of problems.js

const Leveldown = require('leveldown');
const async = require('async');
 
const KEYS = 10000;

const options =  {
  createIfMissing : true,
  errorIfExists : false,
  compression : true,
  cacheSize : 8 << 20,
  writeBufferSize : 4 << 20,
  maxOpenFiles : 64,
  maxFileSize : 2 << 20,
  paranoidChecks : false,
  memory : false,
  sync : false,
  mapSize : 256 * (1024 << 20),
  writeMap : false,
  noSubdir : true,
  bufferKeys : true,
}

const iteratorOptions = {
  gte : 0,
  lte : KEYS,
  gt : null,
  lt : null,
  keys : true,
  values : true,
  fillCache : false,
  keyAsBuffer : true,
  valueAsBuffer : true,
  reverse : false,
  highWaterMark : 16 * 1024
}

const db = [];

for (let i = 0; i < 10; i++) {
  db.push(new Leveldown(`./test-${i}`));
}

const batch = [];

for (let i = 0; i < KEYS; i++) {
  batch.push({ type: 'del', key: i});
  batch.push({ type: 'put', key: i, value: 'v' + i });
}

async.waterfall([
  // simple open/close
  db[0].open.bind(db, options),
  db[0].close.bind(db),
  log.bind(null, 'simple open/close -- api'),



  // simple open close direct bindings
  db[1].binding.open.bind(db[1].binding, options),
  db[1].binding.close.bind(db[1].binding),
  log.bind(null, 'simple open/close -- bindings'),



  // try to close while writting
  db[2].open.bind(db[2], options),
  (cb) => {
    const puts = [];

    for (let i = 0; i < KEYS; i++) {
      puts.push(db[2].put.bind(db[2], i, 'v' + i));
    }

    async.parallel(puts, (err) => {
      console.log('Finished parallel puts -- api');
    });
 
    // don't wait for puts
    cb();
  },
  db[2].close.bind(db[2]),
  log.bind(null, 'write async and close -- api'),



  // try to close while writting
  db[3].binding.open.bind(db[3].binding, options),
  (cb) => {
    const puts = [];

    for (let i = 0; i < KEYS; i++) {
      puts.push(db[3].binding.put.bind(db[3].binding, i, 'v' + i));
    }

    async.parallel(puts, (err) => {
      console.log('Finished parallel puts -- binding');
    });
 
    // don't wait for puts
    cb();
  },
  db[3].binding.close.bind(db[3].binding),
  log.bind(null, 'write async and close -- binding'),



  // try batch putting
  db[4].open.bind(db[4], options),
  (cb) => {
    db[4].batch(batch, log.bind(null, 'batch finished'));
    //db[4].batch(batch, cb);

    // don't wait for batch
    cb();
  },
  db[4].close.bind(db[4]),
  log.bind(null, 'batch write and close -- api'),



  // try batch putting
  db[5].binding.open.bind(db[5].binding, options),
  log.bind(null, 'opened batching -- binding'),
  (cb) => {
    db[5].binding.batch(batch, log.bind(null, 'batch finished'));
    //db[5].binding.batch(batch, cb);

    // don't wait for batch
    log('batch starteded')
    cb();
  },
  log.bind(null, 'closing batch -- binding'),
  db[5].binding.close.bind(db[5].binding),
  log.bind(null, 'batch write and close -- binding'),



  // test iterators
  db[6].open.bind(db[6], options),
  (cb) => {
    let iterator = db[6].iterator(iteratorOptions);

    iterator.next(function process(...args) {
      if (args.length === 0) {
        console.log('the finished...');
        return;
      }

      if (args[0]) {
        console.log('Error:', args[0].message);
        return;
      }

      setImmediate(() => {
        iterator.next(process);
      })
    })

    cb();
  },
  db[6].close.bind(db[6]),
  log.bind(null, 'iterator and close'),



  db[7].binding.open.bind(db[7].binding, options),
  (cb) => {
    let iterator = db[7].binding.iterator(iteratorOptions);

    iterator.next(function process(...args) {
      if (args.length === 0) {
        console.log('the finished...');
        return;
      }

      if (args[0]) {
        console.log('Binding: Error:', args[0].message);
        return;
      }

      setImmediate(() => {
        iterator.next(process);
      })
    })

    cb();
  },
  db[7].binding.close.bind(db[7].binding),
  log.bind(null, 'iterator and close'),


], (err) => {
  if (err) {
    console.error('!!!! Fail');
    console.error(err);
    return;
  }

  console.log('All tests succeed Success');
});

function log(message, cb) {
  console.log(message);
  if (typeof cb === 'function') {
    cb();
  } else if (cb) {
    console.log(cb)
  }
}