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Check if array is empty

0 likes • Nov 19, 2022
JavaScript
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Generate a random HEX color

AustinLeath
0 likes • Nov 18, 2022
JavaScript
// Generate a random HEX color
randomColor = () => `#${Math.random().toString(16).slice(2, 8).padStart(6, '0')}`;
// Or
const randomColor = () => `#${(~~(Math.random()*(1<<24))).toString(16)}`;

doubly linked list

CodeCatch
0 likes • Nov 19, 2022
JavaScript
class DoublyLinkedList {
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, previous: previousNode };
if (previousNode) previousNode.next = node;
if (nextNode) nextNode.previous = 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] || null;
const nextNode = this.nodes[index + 1] || null;
if (previousNode) previousNode.next = nextNode;
if (nextNode) nextNode.previous = previousNode;
return this.nodes.splice(index, 1);
}
clear() {
this.nodes = [];
}
reverse() {
this.nodes = this.nodes.reduce((acc, { value }) => {
const nextNode = acc[0] || null;
const node = { value, next: nextNode, previous: null };
if (nextNode) nextNode.previous = node;
return [node, ...acc];
}, []);
}
*[Symbol.iterator]() {
yield* this.nodes;
}
}
const list = new DoublyLinkedList();
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.tail.previous.value; // 5
[...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

Clone an array

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// `arr` is an array
const clone = arr => arr.slice(0);
// Or
const clone = arr => [...arr];
// Or
const clone = arr => Array.from(arr);
// Or
const clone = arr => arr.map(x => x);
// Or
const clone = arr => JSON.parse(JSON.stringify(arr));
// Or
const clone = arr => arr.concat([]);

MongoDB Connection

CodeCatch
0 likes • Oct 15, 2022
JavaScript
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();
});

Monotonic Array

CodeCatch
0 likes • Nov 19, 2022
JavaScript
// Time Complexity : O(N)
// Space Complexity : O(1)
var isMonotonic = function(nums) {
let isMono = null;
for(let i = 1; i < nums.length; i++) {
if(isMono === null) {
if(nums[i - 1] < nums[i]) isMono = 0;
else if(nums[i - 1] > nums[i]) isMono = 1;
continue;
}
if(nums[i - 1] < nums[i] && isMono !== 0) {
return false;
}
else if(nums[i - 1] > nums[i] && isMono !== 1) {
return false;
}
}
return true;
};
let nums1 = [1,2,2,3]
let nums2 = [6,5,4,4]
let nums3 = [1,3,2]
console.log(isMonotonic(nums1));
console.log(isMonotonic(nums2));
console.log(isMonotonic(nums3));

Canvas File Downloader

AustinLeath
0 likes • Nov 18, 2022
JavaScript
results =
{
"11345240":"Media Comment-80e47004-1719-493a-af69-a43b2652b41c",
"11345282":"zoom_3_22_21.mp4",
"11345303":"Recording-2.m4a",
"11345348":"February 12%2C 2021.mp4",
"11345826":"Lecture_Rousso_Chapter_06-2.pptx",
"11345933":"Themes_InClassAssigment.pptx",
"11346193":"Agenda – Week of March23.pptx",
"11346318":"MUJS 2370 SP2021 Updated Rhythm Changes Drills Bb - Score.pdf",
"11346319":"MUJS 2370 SP2021 Updated Rhythm Changes Drills C - Score.pdf",
"11346322":"MUJS 2370 SP2021 Updated Rhythm Changes Drills Eb - Score.pdf",
"11346323":"MUJS 2370 Updated Rhythm Changes Drills Bass - Score.pdf",
"11346381":"Anthropology with colored highlighter analysis - Mar 22 2021 - 10-36 AM.pdf",
"11346449":"Anthropology with colored highlighter analysis - Mar 22 2021 - 10-36 AM.pdf",
"11346450":"MUJS 2370 SP2021 Updated Rhythm Changes Drills Bb - Score.pdf",
"11346451":"MUJS 2370 SP2021 Updated Rhythm Changes Drills C - Score.pdf",
"11346453":"MUJS 2370 SP2021 Updated Rhythm Changes Drills Eb - Score.pdf",
"11346454":"MUJS 2370 Updated Rhythm Changes Drills Bass - Score.pdf",
"11346495":"Steinel chromatic ornamentation étude rhythm changes - Aug 23 2020 - 12-19 PM.pdf",
"11346532":"Media Comment-136242b4-7f2c-4d5d-8aa4-091f07e797cf",
"11346581":"2019 Trust Based Relationship Intervention Manual.pdf",
"11346584":"TBRI ppt.pptx",
"11346593":"Trauma informed care.ppt"
}
function NewTab(testing) {
window.open(testing, "_blank");
}
for(test in results) {
var testing = 'https://unt.instructure.com/files/' + test + '/download';
NewTab(testing);
//window.open = 'https://unt.instructure.com/files/' + test + '/download';
}