Private Blockchain

This is an example of how to create a very basic private blockchain using Javascript and LevelDB to keep the blocks stored in the disk.

Installation

Install Node.js
Install dependencies

npm install

How to use

Run the main file calles simpleChain.js by running the command below:

node simpleChain.js

You will see the output in the console for the blocks that are created, by default there are 4 blocks being created.

The chain is being validated and then error is introduced and validated again, showing the errors at the end.

Screnshots

Using the library

To start a new blockchain please call the initBlockchain function directly on a Blockchain object. e.g.

  Blockchain.initBlockchain().then(async (bc) => {
    // Current Height
    let currentBlockHeigh = await bc.getBlockHeight();
  }

The bc parameter will contain a new Blockchain object ready to start calling async functions like:


Blockchain.initBlockchain().then(async (bc) => {

// Getting the current height of the blockchain
const height = await bc.getBlockHeight();

// Adding a new block
const block1 = await bc.addBlock(new Block(`Block example}`));

// Validate chain
const chainErrors = await bc.validateChain();

...

}

Storage

The blockchain will be saved by default in a folder called privatechain located inside the folder where the application is being run.