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Bitwise XOR operator

Nov 19, 2022CodeCatch
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More JavaScript Posts

Untitled

Apr 14, 2023Helper

0 likes • 8 views

const quickSort = arr => {
const a = [...arr];
if (a.length < 2) return a;
const pivotIndex = Math.floor(arr.length / 2);
const pivot = a[pivotIndex];
const [lo, hi] = a.reduce(
(acc, val, i) => {
if (val < pivot || (val === pivot && i != pivotIndex)) {
acc[0].push(val);
} else if (val > pivot) {
acc[1].push(val);
}
return acc;
},
[[], []]
);
return [...quickSort(lo), pivot, ...quickSort(hi)];
};
console.log(quickSort([1, 6, 1, 5, 3, 2, 1, 4])) // [1, 1, 1, 2, 3, 4, 5, 6]

Send mail with nodemailer

Nov 18, 2022AustinLeath

0 likes • 4 views

"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);

MongoDB Connection

Oct 15, 2022CodeCatch

3 likes • 4 views

const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
// Connection URL
const url = 'mongodb://localhost:27017';
// Database Name
const dbName = 'myproject';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, client) {
assert.equal(null, err);
console.log("Connected successfully to server");
const db = client.db(dbName);
client.close();
});

Tree Traversal

Oct 16, 2023C S

0 likes • 8 views

class TreeNode {
constructor(data, depth) {
this.data = data;
this.children = [];
this.depth = depth;
}
}
function buildNaryTree(hosts) {
const nodeMap = {};
// Step 1: Create a map of nodes using fqdn as the key
hosts.forEach((host) => {
nodeMap[host.fqdn] = new TreeNode(host, 0); // Initialize depth to 0
});
// Step 2: Iterate through the array and add each node to its parent's list of children
hosts.forEach((host) => {
if (host.displayParent) {
if (nodeMap[host.displayParent]) {
const parent = nodeMap[host.displayParent];
const node = nodeMap[host.fqdn];
node.depth = parent.depth + 1; // Update the depth
parent.children.push(node);
} else {
console.error(`Parent with fqdn ${host.displayParent} not found for ${host.fqdn}`);
}
}
});
// Find the root nodes (nodes with no parent)
const rootNodes = hosts.filter((host) => !host.displayParent).map((host) => nodeMap[host.fqdn]);
return rootNodes;
}
function treeToObjects(node) {
const result = [];
function inOrder(node) {
if (!node) {
return;
}
// Visit the current node and add it to the result
result.push(node.data);
// Visit children nodes first
node.children.forEach((child) => {
inOrder(child);
});
}
inOrder(node);
return result;
}
// Usage example
const hosts = [
{
fqdn: 'fqdn_1',
display_name: 'Host 1',
},
{
fqdn: 'fqdn_2',
display_name: 'Host 2',
displayParent: 'fqdn_1',
},
{
fqdn: 'fqdn_3',
display_name: 'Host 3'
},
{
fqdn: 'fqdn_4',
display_name: 'Host 4',
displayParent: 'fqdn_3',
},
{
fqdn: 'fqdn_5',
display_name: 'Host 5',
displayParent: 'fqdn_1',
},
];
const tree = buildNaryTree(hosts);
// Function to convert the tree to an array of objects
function convertTreeToArray(nodes) {
const result = [];
nodes.forEach((node) => {
result.push(...treeToObjects(node));
});
return result;
}
// Convert the tree back to an array of objects
const arrayFromTree = convertTreeToArray(tree);
console.log(arrayFromTree);

linked list

Nov 19, 2022CodeCatch

0 likes • 1 view

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

Heroku Production Build

Mar 11, 2021C S

1 like • 1 view

if (process.env.NODE_ENV === "production") {
app.use(express.static("client/build"));
app.get("*", (req, res) => {
res.sendFile(path.resolve(__dirname, "client", "build", "index.html"));
});
}