SimpleBlockchainCreateBlockchain.js

const createBlockchain = num => {
  const blockchain = [createGenesisBlock()];
  let previousBlock = blockchain[0];

  for (let i = 1; i < num; i += 1) {
    const blockToAdd = nextBlock(previousBlock, `This is block #${i}`);
    blockchain.push(blockToAdd);
    previousBlock = blockToAdd;
  }
  console.log(blockchain);
};

const lengthToCreate = 20;
createBlockchain(lengthToCreate);