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require("dotenv").config();const mongoose = require("mongoose");const db = process.env.MONGO_URI;const connectDB = async () => {try {await mongoose.connect(db, {useNewUrlParser: true,useUnifiedTopology: true,useFindAndModify: false,useCreateIndex: true});console.log("MongoDB Connected");} catch (err) {console.error(err.message);}};module.exports = connectDB;
const luhnCheck = num => {let arr = (num + '').split('').reverse().map(x => parseInt(x));let lastDigit = arr.splice(0, 1)[0];let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val *= 2) > 9 ? val - 9 : val)),0);sum += lastDigit;return sum % 10 === 0;};luhnCheck('4485275742308327'); // trueluhnCheck(6011329933655299); // trueluhnCheck(123456789); // false
const toFixed = (n, fixed) => ~~(Math.pow(10, fixed) * n) / Math.pow(10, fixed);// ExamplestoFixed(25.198726354, 1); // 25.1toFixed(25.198726354, 2); // 25.19toFixed(25.198726354, 3); // 25.198toFixed(25.198726354, 4); // 25.1987toFixed(25.198726354, 5); // 25.19872toFixed(25.198726354, 6); // 25.198726
const bucketSort = (arr, size = 5) => {const min = Math.min(...arr);const max = Math.max(...arr);const buckets = Array.from({ length: Math.floor((max - min) / size) + 1 },() => []);arr.forEach(val => {buckets[Math.floor((val - min) / size)].push(val);});return buckets.reduce((acc, b) => [...acc, ...b.sort((a, b) => a - b)], []);};bucketSort([6, 3, 4, 1]); // [1, 3, 4, 6]
function Welcome(props) {return <h1>Hello, {props.name}</h1>;}function App() {return (<div><Welcome name="Sara" /><Welcome name="Cahal" /><Welcome name="Edite" /></div>);}ReactDOM.render(<App />,document.getElementById('root'));
const euclideanDistance = (a, b) =>Math.hypot(...Object.keys(a).map(k => b[k] - a[k]));euclideanDistance([1, 1], [2, 3]); // ~2.2361euclideanDistance([1, 1, 1], [2, 3, 2]); // ~2.4495