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Flatten an array

Nov 19, 2022CodeCatch
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luhnCheck implementation

Nov 19, 2022CodeCatch

0 likes • 2 views

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'); // true
luhnCheck(6011329933655299); // true
luhnCheck(123456789); // false

Global Variables

Oct 29, 2020LeifMessinger

0 likes • 1 view

let variableSet = JSON.parse('["parent","opener","top","length","frames","closed","location","self","window","document","name","customElements","history","locationbar","menubar","personalbar","scrollbars","statusbar","toolbar","status","frameElement","navigator","origin","external","screen","innerWidth","innerHeight","scrollX","pageXOffset","scrollY","pageYOffset","visualViewport","screenX","screenY","outerWidth","outerHeight","devicePixelRatio","clientInformation","screenLeft","screenTop","defaultStatus","defaultstatus","styleMedia","onsearch",&qu...find","webkitRequestAnimationFrame","webkitCancelAnimationFrame","fetch","btoa","atob","setTimeout","clearTimeout","setInterval","clearInterval","createImageBitmap","close","focus","blur","postMessage","onappinstalled","onbeforeinstallprompt","crypto","indexedDB","webkitStorageInfo","sessionStorage","localStorage","chrome","onpointerrawupdate","speechSynthesis","webkitRequestFileSystem","webkitResolveLocalFileSystemURL","openDatabase","variableSet","TEMPORARY","PERSISTENT","addEventListener","removeEventListener","dispatchEvent"]');
let answer = [];
for(let v in this) if(!variableSet.includes(v)) answer.push(v);
console.log(answer);

Simple Express Server

Oct 15, 2022CodeCatch

1 like • 235 views

const express = require('express')
const app = express()
const port = 3000
app.get('/', (req, res) => {
res.send('Hello World!')
})
app.listen(port, () => {
console.log(`Example app listening on port ${port}`)
})

URL Search Term Generator

Jan 17, 2021C S

0 likes • 0 views

const getSearchTerm = delimiter => {
let searchTerm = "";
for (let i = 1; i < commands.length - 1; i++)
searchTerm = searchTerm + commands[i] + delimiter;
searchTerm += commands[commands.length - 1];
return searchTerm;
};

Mongoose DB Connection

Mar 11, 2021C S

0 likes • 0 views

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;

power set

Nov 19, 2022CodeCatch

0 likes • 2 views

const powerset = arr =>
arr.reduce((a, v) => a.concat(a.map(r => r.concat(v))), [[]]);
powerset([1, 2]); // [[], [1], [2], [1, 2]]