Blockchain Lite (JavaScript Edition)

blockchain-lite library / module - build your own blockchain with crypto hashes - revolutionize the world with blockchains, blockchains, blockchains one block at a time

What's a Blockchain?

A blockchain is a distributed database with a list (that is, chain) of records (that is, blocks) linked and secured by digital fingerprints (that is, crypto hashes).

See the Awesome Blockchains page for more.

Usage

Let's get started. Build your own blockchain one block at a time. Example:

const Blocks = require ( " blockchain-lite " ) let Block = Blocks . basic let b0 = Block . first ( ' Genesis ' ) let b1 = Block . next ( b0 , ' Transaction Data... ' ) let b2 = Block . next ( b1 , ' Transaction Data...... ' ) let b3 = Block . next ( b2 , ' More Transaction Data... ' ) let blockchain = [ b0 , b1 , b2 , b3 ] console . log ( blockchain )

will log something like:

[ Block { index: 0, timestamp: 2017-09-25 17:03:38, data: 'Genesis', previousHash: '0', hash: '08f4fa71628c5bc6b430228738bc8c41afaf508ece0b1cf9c9cac53d02e11829' }, Block { index: 1, timestamp: 2017-09-25 17:13:38, data: 'Transaction Data...', previousHash: '08f4fa71628c5bc6b430228738bc8c41afaf508ece0b1cf9c9cac53d02e11829', hash: '740a4aeb3441484c96d1e7f63d31b716220ccee3b6fe94547cae2afbb6010626' }, Block { index: 2, timestamp: 2017-09-25 17:23:38, data: 'Transaction Data......', previousHash: '740a4aeb3441484c96d1e7f63d31b716220ccee3b6fe94547cae2afbb6010626', hash: '28b6892a069e2ff7f1c3128ab495d7cd9b9b1636a51a7f69db93a14b1ee6b1a7' }, Block { index: 3, timestamp: 2017-09-25 17:33:38, data: 'More Transaction Data...', previousHash: '28b6892a069e2ff7f1c3128ab495d7cd9b9b1636a51a7f69db93a14b1ee6b1a7', hash: '4cc0329b2c0cb32e0451fa3179bd944d4cd0fcf410939172f979e9fd2aa9f5f3' } ]

Blocks

Basic • Proof-of-Work

Supported block types / classes for now include:

Basic

class Block { constructor ( index , data , previousHash ) { this . index = index this . timestamp = new Date ( ) this . data = data this . previousHash = previousHash this . hash = this . calcHash ( ) } calcHash ( ) { var sha = SHA256 . create ( ) sha . update ( this . index . toString ( ) + this . timestamp . toString ( ) + this . data + this . previousHash ) return sha . hex ( ) } ... }

(Source: block-basic.js)

class Block { constructor ( index , data , previousHash ) { this . index = index this . timestamp = new Date ( ) this . data = data this . previousHash = previousHash [ this . nonce , this . hash ] = this . computeHashWithProofOfWork ( ) } calcHash ( ) { var sha = SHA256 . create ( ) sha . update ( this . nonce . toString ( ) + this . index . toString ( ) + this . timestamp . toString ( ) + this . data + this . previousHash ) return sha . hex ( ) } ... }

(Source: block-proof-of-work.js)

Transactions

Let's put the transactions from the (hyper) ledger book from Tulips on the Blockchain! on the blockchain:

From To What Qty Dutchgrown (†) Vincent Tulip Bloemendaal Sunset 10 Keukenhof (†) Anne Tulip Semper Augustus 7 Flowers (†) Ruben Tulip Admiral van Eijck 5 Vicent Anne Tulip Bloemendaal Sunset 3 Anne Julia Tulip Semper Augustus 1 Julia Luuk Tulip Semper Augustus 1 Bloom & Blossom (†) Daisy Tulip Admiral of Admirals 8 Vincent Max Tulip Bloemendaal Sunset 2 Anne Martijn Tulip Semper Augustus 2 Ruben Julia Tulip Admiral van Eijck 2 Teleflora (†) Max Tulip Red Impression 11 Anne Naomi Tulip Bloemendaal Sunset 1 Daisy Vincent Tulip Admiral of Admirals 3 Julia Mina Tulip Admiral van Eijck 1

(†): Grower Transaction - New Tulips on the Market!

let b0 = Block . first ( { from : " Dutchgrown " , to : " Vincent " , what : " Tulip Bloemendaal Sunset " , qty : 10 } , { from : " Keukenhof " , to : " Anne " , what : " Tulip Semper Augustus " , qty : 7 } ) let b1 = Block . next ( b0 , { from : " Flowers " , to : " Ruben " , what : " Tulip Admiral van Eijck " , qty : 5 } , { from : " Vicent " , to : " Anne " , what : " Tulip Bloemendaal Sunset " , qty : 3 } , { from : " Anne " , to : " Julia " , what : " Tulip Semper Augustus " , qty : 1 } , { from : " Julia " , to : " Luuk " , what : " Tulip Semper Augustus " , qty : 1 } ) let b2 = Block . next ( b1 , { from : " Bloom & Blossom " , to : " Daisy " , what : " Tulip Admiral of Admirals " , qty : 8 } , { from : " Vincent " , to : " Max " , what : " Tulip Bloemendaal Sunset " , qty : 2 } , { from : " Anne " , to : " Martijn " , what : " Tulip Semper Augustus " , qty : 2 } , { from : " Ruben " , to : " Julia " , what : " Tulip Admiral van Eijck " , qty : 2 } ) ...

resulting in:

[ Block { index: 0, timestamp: 1637-09-25 17:39:21, data: [ { from: 'Dutchgrown', to: 'Vincent', what: 'Tulip Bloemendaal Sunset', qty: 10 }, { from: 'Keukenhof', to: 'Anne', what: 'Tulip Semper Augustus', qty: 7 } ], previousHash: '0', hash: '7cb2df9eee29ca77c99eb4591a25dcbdfa9609aff2bd3558d1a0fe22acd08a51' }, Block { index: 1, timestamp: 1637-09-25 17:49:21, data: [ { from: 'Flowers', to: 'Ruben', what: 'Tulip Admiral van Eijck', qty: 5 }, { from: 'Vicent', to: 'Anne', what: 'Tulip Bloemendaal Sunset', qty: 3 }, { from: 'Anne', to: 'Julia', what: 'Tulip Semper Augustus', qty: 1 }, { from: 'Julia', to: 'Luuk', what: 'Tulip Semper Augustus', qty: 1 } ], previousHash: '7cb2df9eee29ca77c99eb4591a25dcbdfa9609aff2bd3558d1a0fe22acd08a51', hash: 'a7464e98290039f467e7abf6699180205f5151e76b57a79b39f43acc39d75660' }, Block { index: 2, timestamp: 1637-09-25 17:59:21, data: [ { from: 'Bloom & Blossom', to: 'Daisy', what: 'Tulip Admiral of Admirals', qty: 8 }, { from: 'Vincent', to: 'Max', what: 'Tulip Bloemendaal Sunset', qty: 2 }, { from: 'Anne', to: 'Martijn', what: 'Tulip Semper Augustus', qty: 2 }, { from: 'Ruben', to: 'Julia', what: 'Tulip Admiral van Eijck', qty: 2 } ], previousHash: 'a7464e98290039f467e7abf6699180205f5151e76b57a79b39f43acc39d75660', hash: 'b7e4952f801651c1e14d61d77b869d18268b46c468923089f1da33e3959b56b9' }, ... ]

Install

Add the the module to your package e.g.:

$ npm install --save blockchain-lite

-or-

$ yarn add blockchain-lite

License