level-ws

What is level-ws?

The level-ws npm package is a WriteStream implementation for LevelDB, which allows for efficient batch writing of data to a LevelDB database. It is particularly useful for handling large amounts of data that need to be written to the database in a streaming fashion.

What are level-ws's main functionalities?

Batch Writing

This feature allows you to write multiple key-value pairs to a LevelDB database in a batch. The code sample demonstrates how to create a WriteStream and write multiple entries to the database.

const level = require('level');
const levelws = require('level-ws');

const db = level('./mydb');
const ws = levelws(db);

ws.write({ key: 'name', value: 'Alice' });
ws.write({ key: 'age', value: '30' });
ws.end();

Stream Handling

This feature allows you to handle streams of data and pipe them directly into the LevelDB database. The code sample demonstrates how to create a readable stream and pipe it into the WriteStream.

const level = require('level');
const levelws = require('level-ws');
const { Readable } = require('stream');

const db = level('./mydb');
const ws = levelws(db);

const data = [
  { key: 'name', value: 'Alice' },
  { key: 'age', value: '30' }
];

const readable = Readable.from(data);
readable.pipe(ws);

Other packages similar to level-ws

levelup

LevelUP is a Node.js module that provides a higher-level API for interacting with LevelDB. It offers a more user-friendly interface compared to the lower-level LevelDB bindings. While level-ws focuses on WriteStream functionality, LevelUP provides a broader range of database operations including read, write, delete, and batch operations.

leveldown

LevelDOWN is the backend store for LevelDB in Node.js. It provides the low-level bindings to the LevelDB library. While level-ws is specifically for streaming writes, LevelDOWN offers the foundational operations for interacting with LevelDB, such as put, get, and del.

level

The level package is a convenience package that bundles LevelUP and LevelDOWN, providing a simple and easy-to-use interface for working with LevelDB. It offers a comprehensive set of features for database operations, including streaming, but with a more integrated approach compared to the specialized level-ws.

README

level-ws

A basic writable stream for abstract-level databases, using Node.js core streams. This is not a high-performance stream. If benchmarking shows that your particular usage does not fit then try one of the alternative writable streams that are optimized for different use cases.

:pushpin: To instead write data using Web Streams, see level-web-stream.

Usage

If you are upgrading: please see UPGRADING.md.

const { Level } = require('level')
const WriteStream = require('level-ws')

const db = new Level('./db', { valueEncoding: 'json' })
const ws = new WriteStream(db)

ws.on('close', function () {
  console.log('Done!')
})

ws.write({ key: 'alice', value: 42 })
ws.write({ key: 'bob', value: 7 })

// To delete entries, specify an explicit type
ws.write({ type: 'del', key: 'tomas' })
ws.write({ type: 'put', key: 'sara', value: 16 })

ws.end()

API

ws = new WriteStream(db[, options])

Create a writable stream that operates in object mode, accepting batch operations to be committed with db.batch() on each tick of the Node.js event loop. The optional options argument may contain:

• type (string, default: 'put'): default batch operation type if not set on indididual operations.
• maxBufferLength (number, default Infinity): limit the size of batches. When exceeded, the stream will stop processing writes until the current batch has been committed.
• highWaterMark (number, default 16): buffer level when stream.write() starts returning false.

Contributing

Level/level-ws is an OPEN Open Source Project. This means that:

Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.

See the Contribution Guide for more details.

License

MIT

Changelog

[4.0.0] - 2022-07-01

If you are upgrading: please see UPGRADING.md.

Changed

• Breaking: bump readable-stream from 3 to 4 (082b8d6) (Vincent Weevers)
• Breaking: use classes, requiring new (dafafb2) (Vincent Weevers)
• Breaking: drop Node.js 10 (817c30c) (Vincent Weevers)

Fixed

• Cleanup README and add missing docs for options (94a2a8e) (Vincent Weevers).