WIP (BlockchainLocal working)

Signed-off-by: James Zuccon <zuccon@gmail.com>

packages/primitives/src/transaction.ts

@@ -106,4 +106,25 @@ export class Transaction {
   public getLocktime() {
     return this.transaction.locktime;
   }
+
+  public isCoinbase(): boolean {
+    // TODO: This definitely needs checking.
+
+    // A coinbase transaction MUST only have one input.
+    if (this.getInputs().length > 1) {
+      return false;
+    }
+
+    // Get the input's unlocking bytecode.
+    const unlockingBytecode = this.getInputs()[0].unlockingBytecode;
+
+    // Get the firt byte.
+    const firstByte = unlockingBytecode[0];
+
+    if (firstByte >= 0x01 && firstByte <= 0x4b) {
+      return true;
+    }
+
+    return false;
+  }
 }