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binomial coefficient

0 likes • Nov 19, 2022
JavaScript
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Rings and Rods

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// There are n rings and each ring is either red, green, or blue. The rings are distributed across ten rods labeled from 0 to 9.
// You are given a string rings of length 2n that describes the n rings that are placed onto the rods. Every two characters in rings forms a color-position pair that is used to describe each ring where:
// The first character of the ith pair denotes the ith ring's color ('R', 'G', 'B').
// The second character of the ith pair denotes the rod that the ith ring is placed on ('0' to '9').
// For example, "R3G2B1" describes n == 3 rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.
// Return the number of rods that have all three colors of rings on them.
let rings = "B0B6G0R6R0R6G9";
var countPoints = function(rings) {
let sum = 0;
// Always 10 Rods
for (let i = 0; i < 10; i++) {
if (rings.includes(`B${i}`) && rings.includes(`G${i}`) && rings.includes(`R${i}`)) {
sum+=1;
}
}
return sum;
};
console.log(countPoints(rings));

Authenticate Discord User

Test
0 likes • Mar 28, 2023
JavaScript
const Discord = require('discord.js');
const client = new Discord.Client();
const token = 'YOUR_BOT_TOKEN';
// When the bot is ready, log a message to the console
client.on('ready', () => {
console.log(`Logged in as ${client.user.tag}!`);
});
// When a user sends a message, check if they are authenticated
client.on('message', async (msg) => {
if (!msg.author.bot && !msg.author.authenticated) {
const filter = (m) => m.author.id === msg.author.id;
const collector = msg.channel.createMessageCollector(filter, { time: 15000 });
// Send an authentication message to the user
msg.author.send('Please authenticate yourself by clicking this link: ' + generateAuthURL(msg.author.id));
collector.on('collect', async (m) => {
// Check if the message contains the authentication code
if (m.content.startsWith('!auth ')) {
const code = m.content.slice(6);
const { access_token } = await getAccessToken(code);
// Set the user's authenticated status and access token
msg.author.authenticated = true;
msg.author.access_token = access_token;
collector.stop();
}
});
collector.on('end', () => {
if (!msg.author.authenticated) {
msg.author.send('Authentication timed out.');
}
});
}
});
// Generate an authentication URL for the user
function generateAuthURL(userId) {
const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');
const scopes = 'identify';
const clientID = 'YOUR_CLIENT_ID';
return `https://discord.com/api/oauth2/authorize?client_id=${clientID}&redirect_uri=${redirectURI}&response_type=code&scope=${scopes}&state=${userId}`;
}
// Exchange the authorization code for an access token
async function getAccessToken(code) {
const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');
const clientID = 'YOUR_CLIENT_ID';
const clientSecret = 'YOUR_CLIENT_SECRET';
const res = await fetch('https://discord.com/api/oauth2/token', {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded',
},
body: `grant_type=authorization_code&code=${code}&redirect_uri=${redirectURI}&client_id=${clientID}&client_secret=${clientSecret}`,
});
return await res.json();
}
client.login(token);

format duration

CodeCatch
0 likes • Nov 19, 2022
JavaScript
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'

Send mail with nodemailer

AustinLeath
0 likes • Nov 18, 2022
JavaScript
"use strict";
const nodemailer = require("nodemailer");
// async..await is not allowed in global scope, must use a wrapper
async function main() {
// Generate test SMTP service account from ethereal.email
// Only needed if you don't have a real mail account for testing
let testAccount = await nodemailer.createTestAccount();
// create reusable transporter object using the default SMTP transport
let transporter = nodemailer.createTransport({
host: "smtp.ethereal.email",
port: 587,
secure: false, // true for 465, false for other ports
auth: {
user: testAccount.user, // generated ethereal user
pass: testAccount.pass, // generated ethereal password
},
});
// send mail with defined transport object
let info = await transporter.sendMail({
from: '"Fred Foo 👻" <[email protected]>', // sender address
to: "[email protected], [email protected]", // list of receivers
subject: "Hello ✔", // Subject line
text: "Hello world?", // plain text body
html: "<b>Hello world?</b>", // html body
});
console.log("Message sent: %s", info.messageId);
// Message sent: <[email protected]>
// Preview only available when sending through an Ethereal account
console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));
// Preview URL: https://ethereal.email/message/WaQKMgKddxQDoou...
}
main().catch(console.error);

Flatten an array

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);
// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();
// Example
flat(['cat', ['lion', 'tiger']]); // ['cat', 'lion', 'tiger']

linear search

CodeCatch
0 likes • Nov 19, 2022
JavaScript
const linearSearch = (arr, item) => {
for (const i in arr) {
if (arr[i] === item) return +i;
}
return -1;
};
linearSearch([2, 9, 9], 9); // 1
linearSearch([2, 9, 9], 7); // -1