websocket-publish.js

const endpoint =  process.env.IS_OFFLINE ? 'http://localhost:3001' : process.env.PUBLISH_ENDPOINT;
   console.log('publish endpoint', endpoint);
   const gatewayClient = new ApiGatewayManagementApi({
     apiVersion: '2018-11-29',
     credentials: config,
     endpoint,
   });
   return gatewayClient
     .postToConnection({
       ConnectionId: this.connectionId,
       Data: JSON.stringify(message),
     })
     .promise();