fixes lint and test errors

packages/bbob-cli/lib/cli.js

@@ -1,23 +1,24 @@
-'use strict';
-
 const fs = require('fs');
 const program = require('commander');
-const version = require('../package.json').version;
+const { version } = require('../package.json');
 
 program
   .version(version)
   .parse(process.argv);
 
+const options = {};
+
+// eslint-disable-next-line no-unused-vars
 function readFile(filename, encoding, callback) {
   if (options.file === '-') {
     // read from stdin
     const chunks = [];
 
-    process.stdin.on('data', function (chunk) { chunks.push(chunk); });
-
-    process.stdin.on('end', function () {
-      return callback(null, Buffer.concat(chunks).toString(encoding));
+    process.stdin.on('data', (chunk) => {
+      chunks.push(chunk);
     });
+
+    process.stdin.on('end', () => callback(null, Buffer.concat(chunks).toString(encoding)));
   } else {
     fs.readFile(filename, encoding, callback);
   }