Add finalized block info (#104)

packages/backend/src/Block.ts

@@ -0,0 +1,21 @@
+import { Types } from '@dotstats/common';
+
+export default class Block {
+	public static readonly ZERO = new Block(0 as Types.BlockNumber, '' as Types.BlockHash);
+
+	public readonly number: Types.BlockNumber;
+	public readonly hash: Types.BlockHash;
+
+	constructor(number: Types.BlockNumber, hash: Types.BlockHash) {
+		this.number = number;
+		this.hash = hash;
+	}
+
+	gt(other: Block): boolean {
+		return this.number > other.number;
+	}
+
+	eq(other: Block): boolean {
+		return this.number === other.number && this.hash === other.hash;
+	}
+}