function Clock(props) {
  return (
    <div>
      <h1>Hello, world!</h1>
      <h2>It is {props.date.toLocaleTimeString()}.</h2>
    </div>
  );
}

function tick() {
  ReactDOM.render(
    <Clock date={new Date()} />,
    document.getElementById('root')
  );
}

setInterval(tick, 1000);

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');

// Connection URL
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'myproject';

// Use connect method to connect to the server
MongoClient.connect(url, function(err, client) {
  assert.equal(null, err);
  console.log("Connected successfully to server");

  const db = client.db(dbName);

  client.close();
});

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

class LinkedList {
  constructor() {
    this.nodes = [];
  }

  get size() {
    return this.nodes.length;
  }

  get head() {
    return this.size ? this.nodes[0] : null;
  }

  get tail() {
    return this.size ? this.nodes[this.size - 1] : null;
  }

  insertAt(index, value) {
    const previousNode = this.nodes[index - 1] || null;
    const nextNode = this.nodes[index] || null;
    const node = { value, next: nextNode };

    if (previousNode) previousNode.next = node;
    this.nodes.splice(index, 0, node);
  }

  insertFirst(value) {
    this.insertAt(0, value);
  }

  insertLast(value) {
    this.insertAt(this.size, value);
  }

  getAt(index) {
    return this.nodes[index];
  }

  removeAt(index) {
    const previousNode = this.nodes[index - 1];
    const nextNode = this.nodes[index + 1] || null;

    if (previousNode) previousNode.next = nextNode;

    return this.nodes.splice(index, 1);
  }

  clear() {
    this.nodes = [];
  }

  reverse() {
    this.nodes = this.nodes.reduce(
      (acc, { value }) => [{ value, next: acc[0] || null }, ...acc],
      []
    );
  }

  *[Symbol.iterator]() {
    yield* this.nodes;
  }
}

const list = new LinkedList();

list.insertFirst(1);
list.insertFirst(2);
list.insertFirst(3);
list.insertLast(4);
list.insertAt(3, 5);

list.size;                      // 5
list.head.value;                // 3
list.head.next.value;           // 2
list.tail.value;                // 4
[...list.map(e => e.value)];    // [3, 2, 1, 5, 4]

list.removeAt(1);               // 2
list.getAt(1).value;            // 1
list.head.next.value;           // 1
[...list.map(e => e.value)];    // [3, 1, 5, 4]

list.reverse();
[...list.map(e => e.value)];    // [4, 5, 1, 3]

list.clear();
list.size;                      // 0

var arr = [{
    "success": true,
    "data": [
        {
            "id": "ipi_1KrrbvDOiB2klwsKhuqUWqt1",
            "object": "issuing.transaction",
            "amount": -2743,
            "amount_details": {
                "atm_fee": null
            },
            "authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd",
            "balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi",
            "card": "ic_1Krqe5DOiB2klwsK44a35eiE",
            "cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr",
            "created": 1650753567,
            "currency": "usd",
            "dispute": null,
            "livemode": false,
            "merchant_amount": -2743,
            "merchant_currency": "usd",
            "merchant_data": {
                "category": "advertising_services",
                "category_code": "7311",
                "city": "San Francisco",
                "country": "US",
                "name": "Aeros Marketing, LLC",
                "network_id": "1234567890",
                "postal_code": "94103",
                "state": "CA"
            },
            "metadata": {},
            "type": "capture",
            "wallet": null
        },
                {
            "id": "ipi_1Krrbvc62B2klwsKhuqUWqt1",
            "object": "issuing.transaction",
            "amount": -9999,
            "amount_details": {
                "atm_fee": null
            },
            "authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd",
            "balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi",
            "card": "ic_1Krqe5DOiB2klwsK44a35eiE",
            "cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr",
            "created": 1650753567,
            "currency": "USD",
            "dispute": null,
            "livemode": false,
            "merchant_amount": -9999,
            "merchant_currency": "usd",
            "merchant_data": {
                "category": "fast_food",
                "category_code": "7311",
                "city": "San Francisco",
                "country": "US",
                "name": "Aeros Marketing, LLC",
                "network_id": "1234567890",
                "postal_code": "94103",
                "state": "CA"
            },
            "metadata": {},
            "type": "capture",
            "wallet": null
        }
    ]
}];
    

const reduced = arr.reduce((prev, curr) => {
    prev.push({
        amount: curr.data[0].merchant_amount,
        id: curr.data[0].id,
        currency: curr.data[0].currency,
        category: curr.data[0].merchant_data.category
    });
    console.log(prev)

    return prev;
    
}, []);

let nums = [1,2,3,1]

var containsDuplicate = function(nums) {
    let obj = {};
    for(let i =0; i< nums.length; i++){
        if(obj[nums[i]]){
            obj[nums[i]] += 1;
            return true;
        }else{
            obj[nums[i]] = 1;
        }
    }
    return false;
};

console.log(containsDuplicate(nums));