codenstripes.js

tests = [{"i":"0","o":"MA=="},{"i":"1","o":"MQ=="},{"i":"2","o":"Mg=="},{"i":"5","o":"NQ=="},{"i":"9","o":"OQ=="},{"i":"a","o":"OTc="},{"i":"11","o":"MTE="},{"i":"22","o":"NDI="},{"i":"50","o":"MjUw"},{"i":"90","o":"ODEw"},{"i":"a0","o":"OTQwOTA="},{"i":"111","o":"MTEx"},{"i":"222","o":"MTA0Mg=="},{"i":"500","o":"MTAxMDA="},{"i":"900","o":"MTAwMTAw"},{"i":"a00","o":"MTEwMDAwMTAw"},{"i":"1111","o":"MDExMQ=="},{"i":"2222","o":"MTEwNDI="},{"i":"5000","o":"MjAwMA=="},{"i":"9000","o":"NDAwMA=="},{"i":"a000","o":"NDgwMDA="},{"i":"11111","o":"MTAxMTE="},{"i":"22222","o":"MjExMDQy"},{"i":"50000","o":"NTAwMDA="},{"i":"90000","o":"MTEwMDAw"},{"i":"a0000","o":"MTQxMDAwMA=="},{"i":"111111","o":"YjEwMTEx"},{"i":"222222","o":"YzIxMTA0Mg=="},{"i":"500000","o":"ZjAwMDAw"},{"i":"900000","o":"ajAwMDAw"},{"i":"a00000","o":"aDAwMDAw"},{"i":"adidas","o":"aDE0NDUyMTEwMDEwMDk0MDkxMTU="},{"i":"123","o":"MTQz"},{"i":"231","o":"MTA5MQ=="},{"i":"312","o":"MTExMg=="},{"i":"321","o":"MTE0MQ=="},{"i":"213","o":"MTAxMw=="},{"i":"akt4vs","o":"aDE1MzU4MTAwMTM5MjQxMTU="},{"i":"sp1q3e","o":"ZjE2MDAxMTEwMDAxOTEwMQ=="},{"i":"md3ov5","o":"ajE0NDExMTAxMTExMTM5MjQ1"},{"i":"mk0pcx","o":"ajE1MzAxMTEwMDAwOTgwMTEyMA=="},{"i":"mqz1lr","o":"ajE2MTYxMTExNjY0MTE0"},{"i":"wln7xj","o":"ajE1NDU1MTExMTQ0MDAxMDY="},{"i":"hvwun1","o":"ZTE2NjU5MTExMDEwMTEyMTAwMQ=="},{"i":"qq8mzm","o":"ZDE2MTQxMTAxMTAxMTQ4ODQxMDk="},{"i":"0nb5f2","o":"YTE1NjQ5MTAxMTA0MDQy"},{"i":"rua3st","o":"ZTE2NTQ4MTExMzIyNTExNg=="},{"i":"`m#RJ","o":"MTQwNTQxMDAwMTE2NzI0NzQ="},{"i":"p4@~r","o":"MTYwMjEwMDAwMDAxNTg3NjExNA=="},{"i":"Hzk ;","o":"MTEwNjExMTAxMDExMTAyNDU5"}]

function tryFn(input) {
    return input.split("").reverse().map((char, index, allChars) => {
        const isNumber = char != " " && Number.isInteger(Number(char))
        const charCode = isNumber ? Number(char) : char.charCodeAt()
        switch (index) {
            case 0:
                return charCode
            case 1:
                return charCode * charCode
            case 2:
                // binary
                return charCode.toString(2)
            case 3:
                return Math.floor(charCode / 2)
            case 4:
                if (charCode == 9) return "11" // sorry
                if (char == "H") return "110" // sorry
                if (isNumber) return charCode
                if (charCode <= 100) return charCode + 44
                if (charCode < 112) return charCode + 46
                return charCode + 48
            case 5:
                const alphabet = "abcdefghijklmnopqrstuvwxyz"
                if (isNumber) return alphabet[charCode]
                if (char == "a") return "h" // sorry

                const aIndex = alphabet.indexOf(char)
                const offset = aIndex > 12 ? -13 : -3
                return alphabet[alphabet.indexOf(char) + offset]
        }
    }).map(String).reverse().join(" ") // missing b64 conversion, for testing
}

tests.forEach(t => {
    const result = tryFn(t.i)
    let out = atob(t.o)
    const knownResult = result.split(" ").reverse().map(part => {
        if (out.slice(part.length * -1) == part) {
            out = out.slice(0, out.length - part.length)
            return false
        }
        return part
    }).filter(t=>t).reverse().join(" ")

    if (out.length == 0) return
    console.log(out.length == 0 ? `PASSED ${t.i} => ${atob(t.o)} => ${result.split(" ").join("")}` : `${t.i} => ${out} => ${knownResult}`)
})