Simple JavaScript Blockchain

blockchain.js

// Block Object
function Block(previousHash, data) {
  this.previousHash = previousHash;
  this.data = data;
  this.hash = SHA256(JSON.stringify(this));
}

// Blockchain Object
function Blockchain() {

  // Chain of all blocks
  let chain = [];

  // Add block to chain
  this.add = function(data) {
    let previousHash = chain[chain.length - 1].hash;
    let block = new Block(previousHash, data);
    chain.push(block);
  }

  // Print chain to console
  this.print = function() {
    console.log(JSON.stringify(chain, null, 2));
  }

  // Add Genesis Block
  chain.push(new Block('0', 'Genesis Block'));
}