NodeJS app

'use strict';

// CONFIG
const AppSync = {
    "graphqlEndpoint": "...",
    "region": "...",
    "authenticationType": "API_KEY",
    "apiKey": "..."
};

// POLYFILLS
global.WebSocket = require('ws');
global.window = global.window || {
    setTimeout: setTimeout,
    clearTimeout: clearTimeout,
    WebSocket: global.WebSocket,
    ArrayBuffer: global.ArrayBuffer,
    addEventListener: function () { },
    navigator: { onLine: true }
};
global.localStorage = {
    store: {},
    getItem: function (key) {
        return this.store[key]
    },
    setItem: function (key, value) {
        this.store[key] = value
    },
    removeItem: function (key) {
        delete this.store[key]
    }
};
require('es6-promise').polyfill();
require('isomorphic-fetch');

// Require AppSync module
const AUTH_TYPE = require('aws-appsync/lib/link/auth-link').AUTH_TYPE;
const AWSAppSyncClient = require('aws-appsync').default;

// INIT
// Set up AppSync client
const client = new AWSAppSyncClient({
    url: AppSync.graphqlEndpoint,
    region: AppSync.region,
    auth: {
        type: AUTH_TYPE.API_KEY,
        apiKey: AppSync.apiKey
    }
});

// GRAPHQL
const gql = require('graphql-tag');


const OnCommandSubscription = gql(`
subscription OnCreateCommand {
    onCreateCommands2 {
      __typename
      command
      id
      timestamp
      action
    }
  }
`);

const exec = require('child_process').exec;


// APP CODE
client.hydrated().then(function (client) {
    // Now subscribe to results
    const observable = client.subscribe({ query: OnCommandSubscription });

    const realtimeResults = function realtimeResults(data) {
        console.log('(realtime) command: ', data.data.onCreateCommands2);

        let action = data.data.onCreateCommands2.action;
        console.log('action: ', action);

        if (action === "blue") {
            exec("<command>", (err, stdout, stderr) => console.log(stdout));
        } else if (action === "green") {
            exec("<command>", (err, stdout, stderr) => console.log(stdout));
        } else {
            console.log("unknown action: ", action);
        }

    };

    observable.subscribe({
        next: realtimeResults,
        complete: console.log,
        error: console.log,
    });
});