#9 Creating a Block part Three

Author: serranoarevalo

package.json

@@ -11,5 +11,8 @@
   },
   "devDependencies": {
     "tsc-watch": "^1.0.17"
+  },
+  "dependencies": {
+    "crypto-js": "^3.1.9-1"
   }
 }

src/index.ts

@@ -1,9 +1,20 @@
+import * as CryptoJS from "crypto-js";
+
 class Block {
   public index: number;
   public hash: string;
   public previousHash: string;
   public data: string;
   public timestamp: number;
+
+  static calculateBlockHash = (
+    index: number,
+    previousHash: string,
+    timestamp: number,
+    data: string
+  ): string =>
+    CryptoJS.SHA256(index + previousHash + timestamp + data).toString();
+
   constructor(
     index: number,
     hash: string,
@@ -21,8 +32,35 @@ class Block {
 
 const genesisBlock: Block = new Block(0, "2020202020202", "", "Hello", 123456);
 
-let blockchain: [Block] = [genesisBlock];
+let blockchain: Block[] = [genesisBlock];
+
+const getBlockchain = (): Block[] => blockchain;
+
+const getLatestBlock = (): Block => blockchain[blockchain.length - 1];
+
+const getNewTimeStamp = (): number => Math.round(new Date().getTime() / 1000);
+
+const createNewBlock = (data: string): Block => {
+  const previosBlock: Block = getLatestBlock();
+  const newIndex: number = previosBlock.index + 1;
+  const newTimestamp: number = getNewTimeStamp();
+  const newHash: string = Block.calculateBlockHash(
+    newIndex,
+    previosBlock.hash,
+    newTimestamp,
+    data
+  );
+  const newBlock: Block = new Block(
+    newIndex,
+    newHash,
+    previosBlock.hash,
+    data,
+    newTimestamp
+  );
+  return newBlock;
+};
 
-console.log(blockchain);
+console.log(createNewBlock("hello"));
+console.log(createNewBlock("bye bye"));
 
 export {};

yarn.lock

@@ -34,6 +34,10 @@ cross-spawn@^5.1.0:
     shebang-command "^1.2.0"
     which "^1.2.9"
 
+crypto-js@^3.1.9-1:
+  version "3.1.9-1"
+  resolved "https://registry.yarnpkg.com/crypto-js/-/crypto-js-3.1.9-1.tgz#fda19e761fc077e01ffbfdc6e9fdfc59e8806cd8"
+
 duplexer@~0.1.1:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/duplexer/-/duplexer-0.1.1.tgz#ace6ff808c1ce66b57d1ebf97977acb02334cfc1"