roland-checksum

A lightweight module for calculating the Roland Checksum.

• [x] No dependencies
• [x] 100% code coverage
• 6 lines of code

Installation

npm install roland-checksum or yarn add roland-checksum

Usage

var RolandChecksum = require('roland-checksum');

var myNumberArray = [0x20, 0x00, 0x00, 0x74, 0x65, 0x73, 0x74];
var myNumber = 0x20;
var myString = "abcdef";

var myNumberArrayChecksum = RolandChecksum(myNumberArray); //returns 0x20
var myNumberChecksum = RolandChecksum(myNumber); //returns 0x60
var myStringChecksum = RolandChecksum(myString); //returns NaN, since strings can't be checksummed

Tests

You can run the tests by running npm test or yarn test.

We also have istanbul: run npm coverage or yarn coverage.

Calculation

NOTE: This is not the actual code in the module, but it's a simple snippet of code that can help you understand how the calculation works.

var myNumberArray = [0x20, 0x00, 0x00, 0x74, 0x65, 0x73, 0x74];
var checksum = 0x00;

myNumberArray.forEach(function(number){
	checksum += number;
});

checksum %= 128;
checksum = 128 - checksum;