test.js

const {promisify} = require("util");
const {resolve} = require("path");
const fs = require("fs");
const readdir = promisify(fs.readdir);
const stat = promisify(fs.stat);
const {exec} = require("child_process");
var path = require("path");

async function getFiles(dir) {
    const subdirs = await readdir(dir);
    const files = await Promise.all(
        subdirs.map(async (subdir) => {
            const res = resolve(dir, subdir);
            return (await stat(res)).isDirectory() ? getFiles(res) : res;
        })
    );
    return files.reduce((a, f) => a.concat(f), []);
}

getFiles(__dirname)
    .then((files) => {
        files.forEach(function (file) {
            if (path.extname(file) == ".js" && file.indexOf("node_modules") == -1) {
                console.log(
                    " * Checking syntax of",
                    file.replace(__dirname + path.sep, "." + path.sep)
                );
                exec('node --check "' + file + '"', (error, stdout, stderr) => {
                    if (stderr.length > 0) {
                        console.log(`${stderr}`);
                        return;
                    }
                });
            }
        });
    })
    .catch((e) => console.error(e));