Polyfill websocket for nodejs (#80)

package.json

@@ -88,13 +88,16 @@
     "bignumber.js": "^9.1.1",
     "bip66": "^1.1.5",
     "buffer": "^6.0.3",
+    "bufferutil": "^4.0.7",
     "core-js": "^3.27.1",
     "crypto-browserify": "^3.12.0",
     "js-sha3": "^0.8.0",
     "readable-stream": "^4.3.0",
     "secp256k1": "5.0.0",
+    "utf-8-validate": "^6.0.3",
     "utf8": "^3.0.0",
-    "uuid": "^9.0.0"
+    "uuid": "^9.0.0",
+    "ws": "^8.13.0"
   },
   "browser": "./build/icon-sdk-js.web.min.js"
 }

quickstart/example/js/MonitorNodeExample.ts

@@ -0,0 +1,20 @@
+const pkg = require("icon-sdk-js");
+const { HttpProvider, BlockMonitorSpec, Converter, IconService } = pkg;
+
+const NODE_URL = "http://localhost:9090/api/v3";
+const provider = new HttpProvider(NODE_URL + "/icon_dex");
+const iconService = new IconService(provider);
+async function main() {
+  const lastBlock = await iconService.getLastBlock().execute();
+  const height = lastBlock.height;
+  const spec = new BlockMonitorSpec(Converter.toBigNumber(height + 1));
+  const onevent = (data) => {
+    console.log(data);
+  };
+  const onerror = (error) => {
+    console.log(error);
+  };
+  const monitor = iconService.monitorBlock(spec, onevent, onerror);
+}
+
+main().catch((e) => console.log(e));

webpack.config.js

@@ -32,7 +32,11 @@ const setPlugin = target =>
           }
         )
       ]
-    : [];
+    : [
+      new webpack.ProvidePlugin({
+        WebSocket: ['ws', "WebSocket"]
+      })
+    ];
 
 const config = target => ({
   mode,