# @nomicfoundation/ethereumjs-rlp > Recursive Length Prefix Encoding Module Latest version **5.0.4** (published 2024-02-05) · MPL-2.0 license · 0 weekly downloads ## Install ```sh npm install @nomicfoundation/ethereumjs-rlp pnpm add @nomicfoundation/ethereumjs-rlp yarn add @nomicfoundation/ethereumjs-rlp bun add @nomicfoundation/ethereumjs-rlp ``` Provides the command `rlp`. ## Health **Score 45/100 (D)** — status: abandoned. Positive: has types; esm support; no vulnerabilities; high maintenance score; high quality score. Warnings: low downloads. Negative: abandoned. ## Facts | | | |---|---| | Version | 5.0.4 | | Published | 2024-02-05 | | First published | 2022-08-30 | | Weekly downloads | 0 | | License | MPL-2.0 | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Node | >=18 | | Dependencies | 0 | | Unpacked size | 121.6 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 2756 | | Author | martin becze | | Maintainers | schaable, nomic-foundation-publisher, fvictorio, alcuadrado | | Keywords | rlp, ethereum | ## Links - npm: https://www.npmjs.com/package/@nomicfoundation/ethereumjs-rlp - Repository: https://github.com/ethereumjs/ethereumjs-monorepo - Homepage: https://github.com/ethereumjs/ethereumjs-monorepo/tree/master/packages/rlp#readme - Issues: https://github.com/ethereumjs/ethereumjs-monorepo/issues?q=is%3Aissue+label%3A%22package%3A+rlp%22 - npm.io page: https://npm.io/package/@nomicfoundation/ethereumjs-rlp ## Recent versions - 5.0.4 (latest) — 2024-02-05 - 5.0.3 — 2023-10-18 - 5.0.2 — 2023-08-25 - 5.0.1 — 2023-04-15 - 5.0.0 — 2023-03-16 - 4.0.3 — 2023-03-16 - 4.0.2 — 2023-03-16 - 4.0.1 — 2023-03-16 - 4.0.0 — 2022-09-08 - 4.0.0-rc.3 — 2022-09-02 - 4.0.0-rc.2 — 2022-09-01 - 4.0.0-rc.1 — 2022-08-30 ## README # @ethereumjs/rlp [![NPM Package][rlp-npm-badge]][rlp-npm-link] [![GitHub Issues][rlp-issues-badge]][rlp-issues-link] [![Actions Status][rlp-actions-badge]][rlp-actions-link] [![Code Coverage][rlp-coverage-badge]][rlp-coverage-link] [![Discord][discord-badge]][discord-link] | [Recursive Length Prefix](https://ethereum.org/en/developers/docs/data-structures-and-encoding/rlp) encoding for Node.js and the browser. | | ----------------------------------------------------------------------------------------------------------------------------------------- | ## Installation To obtain the latest version, simply require the project using `npm`: ```shell npm install @ethereumjs/rlp ``` Install with `-g` if you want to use the CLI. ## Usage ```ts import assert from 'assert' import { RLP } from '@ethereumjs/rlp' const nestedList = [[], [[]], [[], [[]]]] const encoded = RLP.encode(nestedList) const decoded = RLP.decode(encoded) assert.deepEqual(nestedList, decoded) ``` ## Browser With the breaking release round in Summer 2023 we have added hybrid ESM/CJS builds for all our libraries (see section below) and have eliminated many of the caveats which had previously prevented a frictionless browser usage. It is now easily possible to run a browser build of one of the EthereumJS libraries within a modern browser using the provided ESM build. For a setup example see [./examples/browser.html](./examples/browser.html). ## API `RLP.encode(plain)` - RLP encodes an `Array`, `Uint8Array` or `String` and returns a `Uint8Array`. `RLP.decode(encoded, [stream=false])` - Decodes an RLP encoded `Uint8Array`, `Array` or `String` and returns a `Uint8Array` or `NestedUint8Array`. If `stream` is enabled, it will just decode the first rlp sequence in the Uint8Array. By default, it would throw an error if there are more bytes in Uint8Array than used by the rlp sequence. ### Buffer compatibility If you would like to continue using Buffers like in rlp v2, you can use: ```ts import assert from 'assert' import { arrToBufArr, bufArrToArr } from '@ethereumjs/util' import { RLP } from '@ethereumjs/rlp' const bufferList = [Buffer.from('123', 'hex'), Buffer.from('456', 'hex')] const encoded = RLP.encode(bufArrToArr(bufferList)) const encodedAsBuffer = Buffer.from(encoded) const decoded = RLP.decode(Uint8Array.from(encodedAsBuffer)) // or RLP.decode(encoded) const decodedAsBuffers = arrToBufArr(decoded) assert.deepEqual(bufferList, decodedAsBuffers) ``` ### Buffer -> Uint8Array With the breaking releases from Summer 2023 we have removed all Node.js specific `Buffer` usages from our libraries and replace these with [Uint8Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) representations, which are available both in Node.js and the browser (`Buffer` is a subclass of `Uint8Array`). We have converted existing Buffer conversion methods to Uint8Array conversion methods in the [@ethereumjs/util](https://github.com/ethereumjs/ethereumjs-monorepo/tree/master/packages/util) `bytes` module, see the respective README section for guidance. ### BigInt Support Starting with v4 the usage of [BN.js](https://github.com/indutny/bn.js/) for big numbers has been removed from the library and replaced with the usage of the native JS [BigInt](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) data type (introduced in `ES2020`). Please note that number-related API signatures have changed along with this version update and the minimal build target has been updated to `ES2020`. ## CLI `rlp encode `\ `rlp decode <0x-prefixed hex string>` ### Examples - `rlp encode '5'` -> `0x05` - `rlp encode '[5]'` -> `0xc105` - `rlp encode '["cat", "dog"]'` -> `0xc88363617483646f67` - `rlp decode 0xc88363617483646f67` -> `["cat","dog"]` ## EthereumJS See our organizational [documentation](https://ethereumjs.readthedocs.io) for an introduction to `EthereumJS` as well as information on current standards and best practices. If you want to join for work or carry out improvements on the libraries, please review our [contribution guidelines](https://ethereumjs.readthedocs.io/en/latest/contributing.html) first. ## License [MPL-2.0]() [discord-badge]: https://img.shields.io/static/v1?logo=discord&label=discord&message=Join&color=blue [discord-link]: https://discord.gg/TNwARpR [rlp-npm-badge]: https://img.shields.io/npm/v/@ethereumjs/rlp.svg [rlp-npm-link]: https://www.npmjs.com/package/@ethereumjs/rlp [rlp-issues-badge]: https://img.shields.io/github/issues/ethereumjs/ethereumjs-monorepo/package:%20rlp?label=issues [rlp-issues-link]: https://github.com/ethereumjs/ethereumjs-monorepo/issues?q=is%3Aopen+is%3Aissue+label%3A"package%3A+rlp" [rlp-actions-badge]: https://github.com/ethereumjs/ethereumjs-monorepo/workflows/rlp/badge.svg [rlp-actions-link]: https://github.com/ethereumjs/ethereumjs-monorepo/actions?query=workflow%3A%22rlp%22 [rlp-coverage-badge]: https://codecov.io/gh/ethereumjs/ethereumjs-monorepo/branch/master/graph/badge.svg?flag=rlp [rlp-coverage-link]: https://codecov.io/gh/ethereumjs/ethereumjs-monorepo/tree/master/packages/rlp --- _Source: https://npm.io/package/@nomicfoundation/ethereumjs-rlp · Machine-readable twin of the npm.io package page. 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