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Check if array is empty

0 likes • Nov 19, 2022 • 0 views
JavaScript
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tree traversal

0 likes • Nov 19, 2022 • 1 view
JavaScript
class TreeNode {
constructor(key, value = key, parent = null) {
this.key = key;
this.value = value;
this.parent = parent;
this.children = [];
}
get isLeaf() {
return this.children.length === 0;
}
get hasChildren() {
return !this.isLeaf;
}
}
class Tree {
constructor(key, value = key) {
this.root = new TreeNode(key, value);
}
*preOrderTraversal(node = this.root) {
yield node;
if (node.children.length) {
for (let child of node.children) {
yield* this.preOrderTraversal(child);
}
}
}
*postOrderTraversal(node = this.root) {
if (node.children.length) {
for (let child of node.children) {
yield* this.postOrderTraversal(child);
}
}
yield node;
}
insert(parentNodeKey, key, value = key) {
for (let node of this.preOrderTraversal()) {
if (node.key === parentNodeKey) {
node.children.push(new TreeNode(key, value, node));
return true;
}
}
return false;
}
remove(key) {
for (let node of this.preOrderTraversal()) {
const filtered = node.children.filter(c => c.key !== key);
if (filtered.length !== node.children.length) {
node.children = filtered;
return true;
}
}
return false;
}
find(key) {
for (let node of this.preOrderTraversal()) {
if (node.key === key) return node;
}
return undefined;
}
}
const tree = new Tree(1, 'AB');
tree.insert(1, 11, 'AC');
tree.insert(1, 12, 'BC');
tree.insert(12, 121, 'BG');
[...tree.preOrderTraversal()].map(x => x.value);
// ['AB', 'AC', 'BC', 'BCG']
tree.root.value; // 'AB'
tree.root.hasChildren; // true
tree.find(12).isLeaf; // false
tree.find(121).isLeaf; // true
tree.find(121).parent.value; // 'BC'
tree.remove(12);
[...tree.postOrderTraversal()].map(x => x.value);
// ['AC', 'AB']

Reddit Regex Comment Upvoter

0 likes • May 17, 2021 • 2 views
JavaScript
//Upvotes comments according to a regex pattern. I tried it out on https://www.reddit.com/r/VALORANT/comments/ne74n4/please_admire_this_clip_precise_gunplay_btw/
//Known bugs:
//If a comment was already upvoted, it gets downvoted
//For some reason, it has around a 50-70% success rate. The case insensitive bit works, but I think some of the query selector stuff gets changed. Still, 50% is good
let comments = document.getElementsByClassName("_3tw__eCCe7j-epNCKGXUKk"); //Comment class
let commentsToUpvote = [];
const regexToMatch = /wtf/gi;
for(let comment of comments){
let text = comment.querySelector("._1qeIAgB0cPwnLhDF9XSiJM"); //Comment content class
if(text == undefined){
continue;
}
text = text.textContent;
if(regexToMatch.test(text)){
console.log(text);
commentsToUpvote.push(comment);
}
}
function upvote(comment){
console.log(comment.querySelector(".icon-upvote")); //Just showing you what it's doing
comment.querySelector(".icon-upvote").click();
}
function slowRecurse(){
let comment = commentsToUpvote.pop(); //It's gonna go bottom to top but whatever
if(comment != undefined){
upvote(comment);
setTimeout(slowRecurse,500);
}
}
slowRecurse();

UNT canvas file finder utility

0 likes • Nov 18, 2022 • 0 views
JavaScript
//use this with canvas file finder
function NewTab(testing) {
window.open(testing, "_blank");
}
for(test in results) {
var testing = 'https://unt.instructure.com/files/' + test + '/download';
NewTab(testing);
}

binary search

0 likes • Nov 19, 2022 • 1 view
JavaScript
const binarySearch = (arr, item) => {
let l = 0,
r = arr.length - 1;
while (l <= r) {
const mid = Math.floor((l + r) / 2);
const guess = arr[mid];
if (guess === item) return mid;
if (guess > item) r = mid - 1;
else l = mid + 1;
}
return -1;
};
binarySearch([1, 2, 3, 4, 5], 1); // 0
binarySearch([1, 2, 3, 4, 5], 5); // 4
binarySearch([1, 2, 3, 4, 5], 6); // -1

Function promisification

0 likes • Nov 19, 2022 • 0 views
JavaScript
// promisify(f, true) to get array of results
function promisify(f, manyArgs = false) {
return function (...args) {
return new Promise((resolve, reject) => {
function callback(err, ...results) { // our custom callback for f
if (err) {
reject(err);
} else {
// resolve with all callback results if manyArgs is specified
resolve(manyArgs ? results : results[0]);
}
}
args.push(callback);
f.call(this, ...args);
});
};
}
// usage:
f = promisify(f, true);
f(...).then(arrayOfResults => ..., err => ...);

linked list

0 likes • Nov 19, 2022 • 1 view
JavaScript
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