chore: add --lang option

At this moment it defaults to "js" and everything works as before. But if you pass --lang go it
won't generate JS-related files.

Part of #9

Author: php-coder

package-lock.json

@@ -31,6 +31,7 @@
   },
   "dependencies": {
     "ejs": "~3.1.3",
-    "js-yaml": "~3.14.0"
+    "js-yaml": "~3.14.0",
+    "minimist": "~1.2.5"
   }
 }

package.json

@@ -5,10 +5,24 @@ const ejs = require('ejs');
 const fs = require('fs');
 const path = require('path');
 
+const parseArgs = require('minimist');
+
 const endpointsFile = 'endpoints.yaml';
 const appFile = 'app.js';
 const routesFile = 'routes.js';
 
+const parseCommandLineArgs = (args) => {
+    const opts = {
+        'string': [ 'lang' ],
+        'default': {
+            'lang': 'js'
+        }
+    };
+    const argv = parseArgs(args, opts);
+    //console.debug('argv:', argv);
+    return argv;
+}
+
 const loadConfig = (endpointsFile) => {
     console.log('Read', endpointsFile);
     try {
@@ -108,9 +122,11 @@ const createPackageJson = async (destDir, fileName) => {
     fs.writeFileSync(resultFile, minimalPackageJson);
 };
 
+const argv = parseCommandLineArgs(process.argv.slice(2));
+
 const config = loadConfig(endpointsFile);
 
-let [,, destDir = '.'] = process.argv;
+let destDir = argv._.length > 0 ? argv._[0] : '.';
 destDir = path.resolve(process.cwd(), destDir);
 console.log('Destination directory:', destDir)
 
@@ -119,14 +135,18 @@ if (!fs.existsSync(destDir)) {
     fs.mkdirSync(destDir, {recursive: true});
 }
 
-createApp(destDir, appFile, config);
-createEndpoints(destDir, routesFile, config);
-createPackageJson(destDir, 'package.json');
+if (argv.lang === 'js') {
+    createApp(destDir, appFile, config);
+    createEndpoints(destDir, routesFile, config);
+    createPackageJson(destDir, 'package.json');
+}
 
-console.info(`The application has been generated!
-Use
+console.info('The application has been generated!')
+if (argv.lang === 'js') {
+    console.info(`Use
   npm install
 to install its dependencies and
   export DB_NAME=db DB_USER=user DB_PASSWORD=secret
   npm start
 afteward to run it`);
+}