// define a block

// ##############

​

class Block {

  constructor(index, previousHash, data) {

    this.index = index;

    this.previousHash = previousHash;

    this.timestamp = new Date().getTime() / 1000;

    this.data = data;

    this.hash = calculateHash(index, previousHash, this.timestamp, data);

  }

}

​

// generate genisis block

// ######################

​

​

let poem = "Ode to a Chain of Blocks";

​

let fall = new Block(0, 0, poem);

let blocks = [fall];

​

// generate new block

// ##################

​

function generateNextBlock(blockData) {

  const previousBlock = blocks[blocks.length - 1];

  const nextIndex = previousBlock.index + 1;

  const newBlock = new Block(nextIndex,previousBlock.hash,blockData);

  blocks.push(newBlock);

}

​

// calculate hash

// ##############

​

function calculateHash(index, previousHash, timestamp, data) {

  const str =

    index.toString() +

    previousHash.toString() +

    timestamp.toString() +

    data.toString;

  var h = 0,

    l = str.length,

    i = 0;

  if (l > 0) while (i < l) h = ((h << 5) - h + str.charCodeAt(i++)) | 0;

  return h;

}

​

​

​

function setup() {

  createCanvas(400, 400);

  background(255);

  frameRate(1);

}

​

function draw() {

  if(frameCount < 3){

     this.generateNextBlock(random()+"");

  rectMode(CENTER);noStroke();fill(random(0,255),100);

  rect(random(0,width),random(0,width),5,5);

  console.log(blocks[frameCount-1]); 

  }

​

}

​