added example for signing data

examples/companion_sign_data.js

@@ -0,0 +1,30 @@
+import TCPConnection from "../src/connection/tcp_connection.js";
+import NodeJSSerialConnection from "../src/connection/nodejs_serial_connection.js";
+import {BufferUtils} from "../src/index.js";
+
+// create connection
+const connection = new TCPConnection("10.1.0.75", 5000);
+// const connection = new NodeJSSerialConnection("/dev/cu.usbmodem14401");
+
+// wait until connected
+connection.on("connected", async () => {
+
+    // we are now connected
+    console.log("Connected");
+
+    // sign data
+    try {
+        const signature = await connection.sign(Buffer.from("test"));
+        const signatureHex = BufferUtils.bytesToHex(signature);
+        console.log(signatureHex);
+    } catch(e) {
+        console.log("failed to sign", e);
+    }
+
+    // disconnect
+    await connection.close();
+
+});
+
+// connect to meshcore device
+await connection.connect();