App.js

const apiBaseUrl = "https://i-enjoy-lamp.azurewebsites.net"; 

mounted() {
  let connection = new signalR.HubConnectionBuilder()
    .withUrl(`${apiBaseUrl}/api`).build();

  connection.on(
    "colorChanged",
    (hex) => {
      this.colors = { hex: `#${hex}` };
    }
  );

  connection.start();
}