support custom port for web and api via cli args

src/index.js

@@ -1,6 +1,8 @@
 const path = require('path');
 const express = require('express');
 const protobufjs = require("protobufjs");
+const commandLineArgs = require("command-line-args");
+const commandLineUsage = require("command-line-usage");
 
 // create prisma db client
 const { PrismaClient } = require("@prisma/client");
@@ -11,6 +13,42 @@ BigInt.prototype.toJSON = function() {
     return this.toString();
 }
 
+const optionsList = [
+    {
+        name: 'help',
+        alias: 'h',
+        type: Boolean,
+        description: 'Display this usage guide.'
+    },
+    {
+        name: "port",
+        type: Number,
+        description: "Port to serve web ui and api from.",
+    },
+];
+
+// parse command line args
+const options = commandLineArgs(optionsList);
+
+// show help
+if(options.help){
+    const usage = commandLineUsage([
+        {
+            header: 'Meshtastic Map',
+            content: 'A map of all Meshtastic nodes heard via MQTT.',
+        },
+        {
+            header: 'Options',
+            optionList: optionsList,
+        },
+    ]);
+    console.log(usage);
+    return;
+}
+
+// get options and fallback to default values
+const port = options["port"] ?? 8080;
+
 // load protobufs
 const root = new protobufjs.Root();
 root.resolvePath = (origin, target) => path.join(__dirname, "protos", target);
@@ -377,7 +415,7 @@ app.get('/api/v1/waypoints', async (req, res) => {
 });
 
 // start express server
-const listener = app.listen(8080, () => {
+const listener = app.listen(port, () => {
     const port = listener.address().port;
     console.log(`Server running at http://127.0.0.1:${port}`);
 });