block: add toJSON and fromJSON to Block.

Signed-off-by: Fedor Indutny <fedor@indutny.com>

lib/bcoin/block.js

@@ -107,3 +107,30 @@ Block.prototype._verifyMerkle = function verifyMerkle() {
     return utils.toHex(utils.dsha256(left + right, 'hex'));
   }
 };
+
+Block.prototype.toJSON = function toJSON() {
+  return {
+    v: '1',
+    type: 'block',
+    subtype: this.subtype,
+    hash: this._hash || this.hash('hex'),
+    prevBlock: this.prevBlock,
+    ts: this.ts,
+    block: utils.toHex(bcoin.protocol.framer.block(this, this.subtype))
+  };
+};
+
+Block.fromJSON = function fromJSON(json) {
+  utils.assert.equal(json.v, 1);
+  utils.assert.equal(json.type, 'block');
+
+  var raw = utils.toArray(json.block, 'hex');
+
+  var block = new bcoin.block(json.subtype === 'merkleblock'
+    ? new bcoin.protocol.parser().parseMerkleBlock(raw)
+    : new bcoin.protocol.parser().parseBlock(raw), type);
+
+  block._hash = json.hash;
+
+  return block;
+};