arr = [] // empty array
const isEmpty = arr => !Array.isArray(arr) || arr.length === 0;

// Examples
isEmpty([]); // true
isEmpty([1, 2, 3]); // false

const getTimezone = () => Intl.DateTimeFormat().resolvedOptions().timeZone;

// Example
getTimezone();

//JavaScript program to swap two variables

//take input from the users
let a = prompt('Enter the first variable: ');
let b = prompt('Enter the second variable: ');

//using destructuring assignment
[a, b] = [b, a];

console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);

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;
    
}, []);

const mongoose = require('mongoose')

const UserSchema = new mongoose.Schema({
	username: {
	type: String,
	required: true
	},
	email: {
	type: String,
	unique: true,
	required: true
	},
	password: {
	type: String,
	required: true
	},
	date: {
	type: Date,
	default: Date.now
	}
})

module.exports = User = mongoose.model('user', UserSchema)

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