Convert backend code to ES modules

Bundling code now with Rollup for its flat bundling and tree shaking
support. Front end code still goes through Webpack for browser support.

lib/api-functions.js

@@ -18,15 +18,15 @@
  */
 "use strict";
 
-const crypto = require("crypto");
-const dgram = require("dgram");
-const URL = require("url");
-const http = require("http");
-const config = require("./config");
-const db = require("./db");
-const common = require("./common");
-const auth = require("./auth");
-const cache = require("./cache");
+import crypto from "crypto";
+import dgram from "dgram";
+import URL from "url";
+import http from "http";
+import * as config from "./config";
+import * as db from "./db";
+import * as common from "./common";
+import * as auth from "./auth";
+import * as cache from "./cache";
 
 function udpConReq(address, un, key, callback) {
   if (!address) return false;
@@ -187,7 +187,7 @@ function httpConReq(
     });
 }
 
-function connectionRequest(deviceId, callback) {
+export function connectionRequest(deviceId, callback) {
   const CONNECTION_REQUEST_TIMEOUT = config.get(
     "CONNECTION_REQUEST_TIMEOUT",
     deviceId
@@ -284,7 +284,7 @@ function connectionRequest(deviceId, callback) {
   });
 }
 
-function watchTask(deviceId, taskId, timeout, callback) {
+export function watchTask(deviceId, taskId, timeout, callback) {
   setTimeout(() => {
     db.tasksCollection.findOne(
       { _id: taskId },
@@ -324,7 +324,7 @@ function sanitizeTask(task, callback) {
   callback(task);
 }
 
-function insertTasks(tasks, callback) {
+export function insertTasks(tasks, callback) {
   if (tasks && common.typeOf(tasks) !== common.ARRAY_TYPE) tasks = [tasks];
   else if (!tasks || tasks.length === 0)
     return void callback(null, tasks || []);
@@ -344,7 +344,7 @@ function insertTasks(tasks, callback) {
   }
 }
 
-function deleteDevice(deviceId, callback) {
+export function deleteDevice(deviceId, callback) {
   db.tasksCollection.deleteMany({ device: deviceId }, err => {
     if (err) return void callback(err);
     db.devicesCollection.deleteOne({ _id: deviceId }, err => {
@@ -373,8 +373,3 @@ function deleteDevice(deviceId, callback) {
     });
   });
 }
-
-exports.connectionRequest = connectionRequest;
-exports.watchTask = watchTask;
-exports.insertTasks = insertTasks;
-exports.deleteDevice = deleteDevice;