Forem: ski

CodinGame Clash of Code

ski — Thu, 25 May 2023 15:18:01 +0000

preparin' for an interview? want to sharpen your codin' skills? just want to show that you're a codin' beast?CodinGame is the perfect platform with a plethora of different games an' puzzles to help you.

here i'll focus on Clash of Code. in Clash of Code, up to eight players battle in three different modes an' a multitude of languages for victory. in fastest mode, you're given a prompt an' speed is the name of the game. in reverse mode, you're only given the input an' output an' you need to figure out what the algorithm should be. in shortest mode, you have to program the solution in the least number of characters possible.

after playin' Class of Code with some friends, i set out to binge-code 68 clashes over six days an' currently sit at 429th out of 500,000+ coders. an' here i am to give you a few tips to climb the ranks an' emerge victorious over these fierce clashes between the keyboards.

first, i've only been programmin' in JavaScript for 18 months. i'm no expert, but you don't need to be. the clashes test how fast you can assess a problem, develop a solution, articulate that solution, an' then debug.

for fastest mode, use the language you're most comfortable with. get used to every native method, they'll make your life so much easier.

for reverse mode, you'll need to add an extra step. the very first thin' you should do is to create the prompt from the input an' output. sometimes, it's easy to see what the relation is an' other times, you'll need a piece of scratch paper. (yes, ski uses paper to program. sue me an' blame AP Computer Science A)

for shortest mode, you have to use Ruby. there's no way 'round it. you'll need to get used to Ruby's syntax an' methods, but once you do, that's an easy W.

last but certainly not least, don't cheat. don't plagiarize someone else's code or ask ChatGPT, :). use your own noggin an' keep it fun for everyone.

who doesn't love loopholes

ski — Sun, 12 Mar 2023 01:01:38 +0000

recently, Khan Academy has deprecated their ol' REST API an' transitioned to GraphQL. well, Khan Academy has fostered a large number of amateur devs on its platform who extensively used the API an' the transition to GraphQL meant that peepz on KA couldn't access the API directly anymore due to CORS. until, two minds, one brilliant an' the other not as much, invented an ingenious way to still access the API.

for those unfamiliar with KA, it's filled with all sorts of teenage devs. on the outside, they are hindered by the limitations of KA, stuck with a sandboxed iframe, long outdated syntax, an' only a few CDNs [jsDelivr, cloudflare, etc]. on the inside, they spend way too much time on a crappy educational site that hates 'em, but have created the most absurd workarounds one can think of an' this one might take the cake.

the idea started here when the brilliant mind, WKoA, released this repo which allowed a user to grab the current bitcoin price from a KA program. i'll explain how it works in greater detail in a sec.

i took this idea an' decided to use it with a node.js script an' a friend's library to grab the API data from KA an' store that instead of the bitcoin price. the process is below.

first, GitHub Actions runs our YAML script which is on a schedule. the YAML script imports the library through npm then runs my node.js script.

the node.js script is a lil' complicated after WKoA decided to use XSS to hack the final result, >:(. in a nutshell, it retrieves the API data from KA an' writes the result to a new file that stores the data in an array.

//global constants
const https = require('https')
const fs = require('fs')
const { Client } = require("@bhavjit/khan-api")
const client = new Client()

async function main() {
    //get the replies
    const replies = await client.getAllMessageReplies("ag5zfmtoYW4tYWNhZGVteXJBCxIIVXNlckRhdGEiHmthaWRfMTAzNzkwNDA4MTM5MTE4NzA4MDQ5ODUwNwwLEghGZWVkYmFjaxiAgJOjuLmJCww")
    //cache function variables/constants
    const contestants = [], blacklist = [], teams = ["ninjaz", "astronomers", "leviathans"], regex = {
        join: /\$\[\s*("|')[a-zA-Z0-9 ]+("|')\s*,\s*[0-9]\s*,\s*("|')[A-Za-z0-9 ]+("|')\s*\]\$/,
        username: /(;|function|=>|\/\/|"|'|`)/,
    }
    let comments = ''
    replies.forEach(reply => {
        //the XSS nonsense.
        let string
        try {
            if(!blacklist.includes(reply.author.kaid) && !regex.username.test(reply.author.nickname)){
                //this line is the most important
                if(regex.join.test(reply.text)) string = JSON.parse(reply.text.match(/\[.+\]/))
                else comments += `//WARNING! join failed: ${reply.author.nickname} | ${reply.author.kaid}\n`
            }
            else comments += `//WARNING! blacklisted user attempted to join: ${reply.author.nickname} | ${reply.author.kaid}\n`
        }
        catch (e) { 
            comments += `//ERROR! join failed: ${reply.author.nickname} | ${reply.author.kaid}\n`
            console.error(e) 
        }
        if (string) {
            if(teams.includes(string[2])){
                contestants.push(`{name: "${reply.author.nickname}", kaid: "${reply.author.kaid}", level: ${Math.min(Math.max(string[1], 0), 3)}, team: "${string[2]}"}`)
                console.log(`${reply.author.nickname} joined successfully.`)
            }
            else {
                comments += `//WARNING! invalid join code [team]: ${reply.author.nickname} | ${reply.author.kaid} | ${string[2]}\n`
            }
        }
    })
    //edit the file to match current data
    fs.writeFile('./primaveraContestants.js', `var contestants = [${contestants}]\n${comments}`, err => {
        if (err) console.error(err)
    })

//purge the script
https.get("https://purge.jsdelivr.net/gh/thelegendski/automated@master/primaveraContestants.js");
}
main()

that file is then imported on KA through jsDelivr an' voila!

well, GitHub Actions wouldn't cut it as there was a possibility that i'd have to pay for the minutes that the script ran on the servers, so we transitioned over to Google Apps Script (GAS). i ironically found the script to commit to GitHub from GAS from an ex-KA dev, an' WKoA found a slightly better version of the script here. the link to the complete script can be found here.

currently, the only issue that remains is jsDelivr update times. the GAS script should purge the cached script since jsDelivr claims it was purged, but jsDelivr has smth against truthful results since it doesn't update. we're currently in contact with the jsDelivr support team to see if we can resolve this issue, :).

an' that's all! if KA won't let us access their API, we'll figure it out ourselves, >:).

arguments object in arrow functions

ski — Tue, 03 Jan 2023 11:37:58 +0000

intro

normally, when you write a function, you can call upon the arguments array to loop through the arguments passed into the function as i did here with a function constant.

function foo () {
    console.log(arguments);
}
foo(1);

fix

however, (fat) arrow functions () => {} do not possess an arguments object within their scope as the followin' will produce a reference error.

const foo = () => console.log(arguments);
foo(1);

however, the trick is to cleverly employ the spread operator to create a rest parameter. (technically, arrays are objects, so the rest parameter still counts as an arguments object)

const foo = (...args) => console.log(args);
foo(1);

happy codin'!