Simplify getThreads() (#186)

Author: XhmikosR

lib/getThreads.js

@@ -2,13 +2,9 @@
 
 const os = require('os');
 
-// eslint-disable-next-line unicorn/explicit-length-check
-const CPUS = os.cpus() && os.cpus().length;
-const THREADS = CPUS > 2 ? CPUS - 1 : 1;
-
-function getThreads(config) {
-  const { threads } = config;
+const THREADS = Math.max(os.cpus().length - 1, 1);
 
+function getThreads({ threads }) {
   switch (threads) {
     case 'auto':
     case -1: