// Vanilla JS Solution:
var app = document.getElementById('app');

var typewriter = new Typewriter(app, { loop: true });

typewriter
    .typeString("I'm John and I'm a super cool web developer")
    .pauseFor(3000)
    .deleteChars(13) // "web developer" = 13 characters
    .typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!"
    .start();

// React Solution:
import Typewriter from 'typewriter-effect';

<Typewriter
    options={{ loop: true }}
    onInit={typewriter => {
        typewriter
            .typeString("I'm John and I'm a super cool web developer")
            .pauseFor(3000)
            .deleteChars(13) // "web developer" = 13 characters
            .typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!"
            .start();
    }}
/>

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    for(let i = 0; i < nums.length; i++) {
        for(let j = 0; j < nums.length; j++) {
            if(nums[i] + nums[j] === target && i !== j) {
                return [i, j]
            }
        }
    }
};

const getURLParameters = url =>
(url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(
    (a, v) => (
      (a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a
    ),
    {}
);

const reverse = str => str.split('').reverse().join('');
reverse('hello world');     
// Result: 'dlrow olleh'

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 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]]