I got excited when I saw this, so I made an answer that at least does what the question requires :D
The encoding works through base conversion logic and conversion of those numbers to text. I used an array of length 6 to store the data on encoding to ensure that it will always be 6 chars(and not less)
The decoding works through just adding it back respecting the powers so it adds back in full value
I hope it's an answer you're looking for because I love this question :D
//a homemade answer :D
//first time I saw a question like that, I hope I get stuff like this in college ngl
function encode(num){
let alphabet=[]
for(let i=48;i<127;i++){
alphabet.push(String.fromCharCode(i))
}
//alphabet is filled with encoding text :D
let arr=[0,0,0,0,0,0] //for fixed 6 digits
let pow=0; let pow1=1
let length=alphabet.length
while(num>0){
let subtraction=(num%Math.pow(length,pow1))
num-=subtraction
arr[pow]=subtraction/Math.pow(length,pow)
pow++; pow1++
}
return arr.reverse()
.map(a=>String.fromCharCode(a+48)) //offset of 48 for nice chars
.join('') //like a base conversion basically
}
function decode(string){
let num=0; let length=127-48 //length really is the number of base(79 in this case)
string=string.split('').reverse().join('')
for(let i=0;i<string.length;i++){
let int=string.charCodeAt(i)-48 //-48 remembering the offset
num+=int*Math.pow(length,i)
}
return num
}
var int=12348291
console.log('encoded num:',encode(int))
console.log('decoded string:',decode(encode(int)))
console.log('they are reversible?',decode(encode(int))==int)
