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Depth-First Search in TypeScript

Oct 15, 2022CodeCatch
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langToConfig map

Mar 31, 2023Helper

0 likes • 3 views

const langToConfig = {
'javascript': {
image: '',
cmd: ['']
},
'php': {
image: '',
cmd: ['']
},
}

retryPromise.ts

Oct 20, 2023LeifMessinger

0 likes • 6 views

//Retries maxRetries number of times, meaning that if you have 0, then it'll run the function once.
async function retryPromise<T>(
promiseFn: () => Promise<T>,
maxRetries = 3,
delayOffset = 0,
delayRandomRange = 0
): Promise<T> {
return new Promise<T>((resolve, reject) => {
promiseFn()
.then(resolve, (error: any) => { //On error
if (maxRetries <= 0) {
return reject(error);
} else {
if(delayRandomRange * Math.random() + delayOffset < 1.0){
return retryPromise(promiseFn, maxRetries - 1, delayOffset, delayRandomRange).then(resolve, reject);
}else{
return new Promise<T>((resolveTwo, rejectTwo) => {
setTimeout(() => {
return retryPromise(promiseFn, maxRetries - 1, delayOffset, delayRandomRange).then(resolveTwo, rejectTwo);
}, delayRandomRange * Math.random() + delayOffset);
}).then(resolve, reject);
}
}
});
});
}
//Returns a function that will fail numTimes times, then will return aValue
function functionThatReturnsAFunctionThatFailsACoupleTimes(numTimes: number, aValue: any): () => Promise<any> {
return async function(){
if(numTimes == 0){
return aValue;
}
numTimes--;
throw false;
};
}
const SMALL_NUMBER = 10;
function testTest(failNumberOfTimes: number){
let functionThatFailsACoupleTimes = functionThatReturnsAFunctionThatFailsACoupleTimes(failNumberOfTimes, true);
//Test my test
for(let i = 0; i < (failNumberOfTimes * 2); ++i){
function evalTest(val: any){
let testTestFailedReason = "";
if(val === undefined){
testTestFailedReason = "Test test returned undefined for some reason.";
}
if((i + 1) > failNumberOfTimes){
if(val === true){
//We're good
}else{
testTestFailedReason = "Test test didn't return true when it should have.";
}
}else{
if(val === false){
//We're good
}else{
testTestFailedReason = "Test test didn't return false when it should have.";
}
}
testTestFailedReason = testTestFailedReason || "Test test passed test case";
console.log(testTestFailedReason, "at index", i, "where the function returned", val);
}
functionThatFailsACoupleTimes().then(evalTest, evalTest)
};
}
testTest(SMALL_NUMBER);
let testCaseCounter = 1;
const throwsNoError = [
(val: any) => {
if(val == true){
console.log("Passed test case " + testCaseCounter++);
}else{
console.error("Unexpected return value", val);
}
},
() => {
console.error("It wasn't supposed to fail!")
}
]
const throwsError = [
(val: any) => {
console.error("It wasn't supposed to succeed!", val);
},
(val: any) => {
if(val == false){
console.log("Passed test case " + testCaseCounter++);
}else{
console.error("Unexpected return value", val);
}
}
];
//Runs SMALL_NUMBER times, because SMALL_NUMBER - 1 is the number of retries after the first one
let functionThatFailsACoupleTimes = functionThatReturnsAFunctionThatFailsACoupleTimes(SMALL_NUMBER - 1, true);
retryPromise(functionThatFailsACoupleTimes, SMALL_NUMBER - 1).then(...throwsNoError)
functionThatFailsACoupleTimes = functionThatReturnsAFunctionThatFailsACoupleTimes(SMALL_NUMBER - 1, true);
//Runs SMALL_NUMBER - 1 times, because SMALL_NUMBER - 2 is the number of retries after the first one
retryPromise(functionThatFailsACoupleTimes, SMALL_NUMBER - 2).then(...throwsError)
//Testing the delay. You'll have to wait a bit too.
functionThatFailsACoupleTimes = functionThatReturnsAFunctionThatFailsACoupleTimes(SMALL_NUMBER - 1, true);
//Runs SMALL_NUMBER times, because SMALL_NUMBER - 1 is the number of retries after the first one
retryPromise(functionThatFailsACoupleTimes, SMALL_NUMBER - 1, 500, 500).then(...throwsNoError)
functionThatFailsACoupleTimes = functionThatReturnsAFunctionThatFailsACoupleTimes(SMALL_NUMBER - 1, true);
//Runs SMALL_NUMBER - 1 times, because SMALL_NUMBER - 2 is the number of retries after the first one
retryPromise(functionThatFailsACoupleTimes, SMALL_NUMBER - 2, 500, 500).then(...throwsError)

class based task manager

Jun 1, 2023CodeCatch

0 likes • 3 views

interface Task {
id: number;
title: string;
completed: boolean;
}
class TaskManager {
private tasks: Task[] = [];
constructor() {}
addTask(title: string) {
const taskId = this.tasks.length + 1;
const task: Task = {
id: taskId,
title,
completed: false,
};
this.tasks.push(task);
}
markTaskAsComplete(taskId: number) {
const task = this.tasks.find((task) => task.id === taskId);
if (task) {
task.completed = true;
}
}
markTaskAsIncomplete(taskId: number) {
const task = this.tasks.find((task) => task.id === taskId);
if (task) {
task.completed = false;
}
}
listTasks() {
console.log('Tasks:');
this.tasks.forEach((task) => {
console.log(`${task.id}. [${task.completed ? 'X' : ' '}] ${task.title}`);
});
}
}
// Example usage:
const taskManager = new TaskManager();
taskManager.addTask('Buy groceries');
taskManager.addTask('Pay bills');
taskManager.addTask('Clean the house');
taskManager.listTasks();
// Output:
// Tasks:
// 1. [ ] Buy groceries
// 2. [ ] Pay bills
// 3. [ ] Clean the house

React usePrevious Hook

Oct 15, 2022CodeCatch

0 likes • 71 views

import { useState, useEffect, useRef } from "react";
// Usage
function App() {
// State value and setter for our example
const [count, setCount] = useState(0);
// Get the previous value (was passed into hook on last render)
const prevCount = usePrevious(count);
// Display both current and previous count value
return (
<div>
<h1>
Now: {count}, before: {prevCount}
</h1>
<button onClick={() => setCount(count + 1)}>Increment</button>
</div>
);
}
// Hook
function usePrevious(value) {
// The ref object is a generic container whose current property is mutable ...
// ... and can hold any value, similar to an instance property on a class
const ref = useRef();
// Store current value in ref
useEffect(() => {
ref.current = value;
}, [value]); // Only re-run if value changes
// Return previous value (happens before update in useEffect above)
return ref.current;
}

typescript hello

Nov 21, 2023AustinLeath

0 likes • 23 views

// Print Hello, World!
console.log("Hello, World!");

Coderator Follow System CRUD

Nov 18, 2022AustinLeath

1 like • 4 views

const getFollowers = async (req: Request, res: Response) => {
try {
const username = req.params.username || '';
const user = await User.findUnique({
where: { username },
include: { followedBy: true },
});
if (!user) {
res.status(404).json({
error: 'User could not be found',
});
return;
}
const followers = user.followedBy.map(followedBy => {
return {
followerId: followedBy.followerId,
};
});
const followersCount = followers.length;
res.json({ followersCount: followersCount, followers });
} catch (error) {
console.error('getFollowers() error: ', error);
res.status(500).json({
error: `There was an error fetching followers for user with username "${req.params.username}", please try again later`,
});
}
};
const getFollowing = async (req: Request, res: Response) => {
try {
const username = req.params.username || '';
const user = await User.findUnique({
where: { username },
include: { following: true },
});
if (!user) {
res.status(404).json({
error: 'User could not be found',
});
return;
}
const following = user.following.map(following => {
return {
followingId: following.followingId,
};
});
const followingCount = following.length;
res.json({ followingCount: followingCount, following });
} catch (error) {
console.error('getFollowing() error: ', error);
res.status(500).json({
error: `There was an error fetching who is following "${req.params.username}", please try again later`,
});
}
};
const followUser = async (req: Request, res: Response) => {
try {
const username = req.params.username || '';
const user = await User.findUnique({
where: { username },
});
if (!user) {
res.status(404).json({
error: 'User could not be found',
});
return;
}
// dont allow a user to follow themselves
if (req.user.id === user.id) {
res.status(400).json({ error: 'You cannot follow yourself' });
return;
}
//check if a follow relationship already exists
const followrelationship = await prisma.follows.findUnique({
where: {
followerId_followingId: {
followerId: req.user.id,
followingId: user.id,
},
},
});
// check if the follow relationship already exists
if (followrelationship) {
res.status(400).json({ error: 'You are already following this user' });
return;
}
// create the follow relationship
const follow = await prisma.follows.create({
data: {
followerId: req.user.id,
followingId: user.id,
},
});
res.json({ follow });
} catch (error) {
console.error('followUser() error: ', error);
res.status(500).json({
error: `There was an error following "${req.params.username}", please try again later`,
});
}
};
const unfollowUser = async (req: Request, res: Response) => {
try {
const username = req.params.username || '';
const user = await User.findUnique({
where: { username },
});
if (!user) {
res.status(404).json({
error: 'User could not be found',
});
return;
}
// dont allow a user to unfollow themselves
if (req.user.id === user.id) {
res.status(400).json({ error: 'You cannot unfollow yourself' });
return;
}
//check if a follow relationship already exists
const followrelationship = await prisma.follows.findUnique({
where: {
followerId_followingId: {
followerId: req.user.id,
followingId: user.id,
},
},
});
// check if the follow relationship already exists
if (!followrelationship) {
res.status(400).json({ error: 'You are not following this user' });
return;
}
// delete the follow relationship
const follow = await prisma.follows.delete({
where: {
followerId_followingId: {
followerId: req.user.id,
followingId: user.id,
},
},
});
res.json({ follow });
} catch (error) {
console.error('unfollowUser() error: ', error);
res.status(500).json({
error: `There was an error unfollowing "${req.params.username}", please try again later`,
});
}
};