const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);

// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();

// Example
flat(['cat', ['lion', 'tiger']]);   // ['cat', 'lion', 'tiger']

alert("bruh")

router.post("/", async (req, res) => {
	const { email, password } = req.body;

	try {
	if (!email) return res.status(400).json({ msg: "An email is required" });

	if (!password)
	return res.status(400).json({ msg: "A password is required" });

	const user = await User.findOne({ email }).select("_id password");

	if (!user) return res.status(400).json({ msg: "Invalid credentials" });

	const match = await bcrypt.compare(password, user.password);

	if (!match) return res.status(400).json({ msg: "Invalid credentials" });

	const accessToken = genAccessToken({ id: user._id });
	const refreshToken = genRefreshToken({ id: user._id });

	res.cookie("token", refreshToken, {
	expires: new Date(Date.now() + 604800),
	httpOnly: true,
	});

	res.json({ accessToken });
	} catch (err) {
	console.log(err.message);
	res.status(500).json({ msg: "Error logging in user" });
	}
});

// `arr` is an array
const clone = arr => arr.slice(0);

// Or
const clone = arr => [...arr];

// Or
const clone = arr => Array.from(arr);

// Or
const clone = arr => arr.map(x => x);

// Or
const clone = arr => JSON.parse(JSON.stringify(arr));

// Or
const clone = arr => arr.concat([]);

# Acronyms

## Computer Numerical Control (CNC)

- Typicalldfdfsdffdafdasgfdgfgfdfdafdasfdafda

const linearSearch = (arr, item) => {
  for (const i in arr) {
    if (arr[i] === item) return +i;
  }
  return -1;
};

linearSearch([2, 9, 9], 9); // 1
linearSearch([2, 9, 9], 7); // -1