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native data structures

Nov 19, 2022CodeCatch
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More JavaScript Posts

find primes

Nov 19, 2022CodeCatch

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const primes = num => {
let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2),
sqroot = Math.floor(Math.sqrt(num)),
numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2);
numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y === x)));
return arr;
};
primes(10); // [2, 3, 5, 7]

Simple Express Server

Oct 15, 2022CodeCatch

1 like • 268 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}`)
})

format duration

Nov 19, 2022CodeCatch

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const formatDuration = ms => {
if (ms < 0) ms = -ms;
const time = {
day: Math.floor(ms / 86400000),
hour: Math.floor(ms / 3600000) % 24,
minute: Math.floor(ms / 60000) % 60,
second: Math.floor(ms / 1000) % 60,
millisecond: Math.floor(ms) % 1000
};
return Object.entries(time)
.filter(val => val[1] !== 0)
.map(([key, val]) => `${val} ${key}${val !== 1 ? 's' : ''}`)
.join(', ');
};
formatDuration(1001); // '1 second, 1 millisecond'
formatDuration(34325055574); // '397 days, 6 hours, 44 minutes, 15 seconds, 574 milliseconds'

Bitwise XOR operator

Nov 19, 2022CodeCatch

0 likes • 1 view

//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: ');
// XOR operator
a = a ^ b
b = a ^ b
a = a ^ b
console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);

JWT Authentication

Mar 11, 2021C S

0 likes • 1 view

const jwt = require("jsonwebtoken");
const authToken = (req, res, next) => {
const token = req.headers["x-auth-token"];
try {
req.user = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);
next();
} catch (err) {
console.log(err.message);
res.status(401).json({ msg: "Error authenticating token" });
}
};
module.exports = authToken;

Generate a random HEX color

Nov 18, 2022AustinLeath

0 likes • 1 view

// Or
const randomColor = () => `#${(~~(Math.random()*(1<<24))).toString(16)}`;
console.log(randomColor);