crc

What is crc?

The crc npm package is used for generating cyclic redundancy check (CRC) codes for various input data. CRC is a popular method for detecting accidental changes to raw data in digital networks and storage devices. The package supports multiple CRC algorithms and can be used in various applications where data integrity is crucial.

What are crc's main functionalities?

CRC32 Calculation

This feature allows the calculation of CRC32 checksum for the input string 'hello world'. It is useful for verifying the integrity of strings or files.

const crc = require('crc');
const result = crc.crc32('hello world');
console.log('CRC32:', result);

CRC16 Calculation

This feature computes the CRC16 checksum for the given string. It's commonly used in telecommunications and storage for error-checking.

const crc = require('crc');
const result = crc.crc16('hello world');
console.log('CRC16:', result);

CRC1 Calculation

This feature calculates a simple CRC1 checksum, which can be used for basic error detection in scenarios where minimal data corruption checks are needed.

const crc = require('crc');
const result = crc.crc1('hello world');
console.log('CRC1:', result);

Other packages similar to crc

crc32

The crc32 package is similar to crc in that it provides CRC32 checksum calculations. However, it focuses solely on CRC32, whereas crc supports multiple algorithms including CRC1, CRC8, CRC16, and others, making crc more versatile.

buffer-crc32

buffer-crc32 is another npm package that offers CRC32 checksum calculations. It is designed to work specifically with Node.js buffers. Compared to crc, buffer-crc32 is more specialized for buffer data types while crc offers broader functionality with support for strings and other data types.

README

crc

The module for calculating Cyclic Redundancy Check (CRC) for Node.js and the Browser.

Features

• Full test suite comparing values against reference pycrc implementation.
• Pure JavaScript implementation, no dependencies.
• ES6 modules.
• Provides CRC tables for optimized calculations.
• Provides support for the following CRC algorithms:
  • CRC1 (crc1)
  • CRC8 (crc8)
  • CRC8 1-Wire (crc81wire)
  • CRC16 (crc16)
  • CRC16 CCITT (crc16ccitt)
  • CRC16 Modbus (crc16modbus)
  • CRC16 Kermit (crc16kermit)
  • CRC16 XModem (crc16xmodem)
  • CRC24 (crc24)
  • CRC32 (crc32)
  • CRCJAM (crcjam)

Installation

npm install crc

Usage

Calculate a CRC32:

import crc32 from 'crc/crc32';
crc32('hello').toString(16);
// "3610a686"

or

const { crc32 } = require('crc');
crc32('hello').toString(16);
// "3610a686"

Calculate a CRC32 of a file:

crc32(fs.readFileSync('README.md', 'utf8')).toString(16);
// "127ad531"

Or using a Buffer:

crc32(fs.readFileSync('README.md')).toString(16);
// "127ad531"

Incrementally calculate a CRC32:

value = crc.crc32('one');
value = crc.crc32('two', value);
value = crc.crc32('three', value);
value.toString(16);
// "9e1c092"

Important: Node >= 6.3.0 < 6.9.2

There's was a bug in Node #9342 that affected CRC calculation if Buffer.split() is used (see issue discussion for details). This affected all version starting from 6.3.0 up to but not including 6.9.2. The patch #9341 was released in 6.9.2. If you are upgrading and seeing odd CRC calculation mismatches, this might be the reason.

Bundling

This library exposes an ES6 module, so if you are using a bundling tool such as Webpack or Rollup, you can just import it, and the bundle will not include unneccesary code:

import crc from 'crc';

crc.crc32('hello').toString(16);
// "3610a686"

Or, alternatively:

import { crc32 } from 'crc';

crc32('hello').toString(16);

Running tests

npm test

Thanks!

pycrc library is which the source of all of the CRC tables.

License

The MIT License (MIT)

Copyright (c) 2014 Alex Gorbatchev

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.