const getSubsets = arr => arr.reduce((prev, curr) => prev.concat(prev.map(k => k.concat(curr))), [[]]);

// Examples
getSubsets([1, 2]);     // [[], [1], [2], [1, 2]]
getSubsets([1, 2, 3]);  // [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]

# Acronyms

## Computer Numerical Control (CNC)

- Typicalldfdfsdffdafdasgfdgfgfdfdafdasfdafda

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var containsDuplicate = function(nums) {
    return new Set(nums).size !== nums.length
};

function copyString(text){
	async function navigatorClipboardCopy(text){
			if(document.location.protocol != "https:"){
					return false;
			}
			return new Promise((resolve, reject)=>{
					navigator.clipboard.writeText(text).then(()=>{resolve(true);}, ()=>{resolve(false);});
			});
	}
	function domCopy(text){
			if(!(document.execCommand)){
					console.warn("They finally deprecated document.execCommand!");
			}

			const input = document.createElement('textarea');
			input.value = text;
			document.body.appendChild(input);
			input.select();
			const success = document.execCommand('copy');
			document.body.removeChild(input);

			return success;
	}
	function promptCopy(){
			prompt("Copy failed. Might have ... somewhere. Check console.", text);
			console.log(text);
	}
	function done(){
			alert("Copied to clipboard");
	}
	navigatorClipboardCopy(text).catch(()=>{return false;}).then((success)=>{
			if(success){
					done();
			}else{
					if(domCopy(text)){
							done();
					}else{
							promptCopy();
					}
			}
	});
}

const union = (...arr) => [...new Set(arr.flat())];

// Example
union([1, 2], [2, 3], [3]);     // [1, 2, 3]

const jwt = require("jsonwebtoken");

const authToken = (req, res, next) => {
	const token = req.headers["x-auth-token"];

	try {
	req.user = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);

	next();
	} catch (err) {
	console.log(err.message);
	res.status(401).json({ msg: "Error authenticating token" });
	}
};

module.exports = authToken;