pixels_camp_challenge_code_golf

/**
 * @param {string} alphabet
 * @param {string} key
 * @param {string} text
 * @return {string}
 */



f = (
  alphabet,
  key,
  text,
  alphabetLength = alphabet.length,
  indexOf = c => alphabet.indexOf(c)
) =>
  [...text]
    .filter(c => ~indexOf(c))
    .map((c, i) =>
      key
        ? alphabet[
            (indexOf(key[i % key.length]) - indexOf(c) + alphabetLength) % alphabetLength
          ]
        : c
    )
    .join("");

const assert = require("assert").strict;
assert.deepEqual(
  f("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "", "MO3VEYOURTROOP3SATZEROTH3REEHUND3RED"),
  "MOVEYOURTROOPSATZEROTHREEHUNDRED"
);

assert.deepEqual(
  f("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "SECRET", "MOVEYOURTROOPSATZEROTHREEHUNDRED"),
  "GQHNGFYNJAQFDMCYFPBQJKNPOXIEBCOB"
);

assert.deepEqual(f("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "SECRET", "abcd"), "");

assert.deepEqual(
  f(
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
    "SECRET",
    "MoOo1£44$24!VEYOURTROOPSATZEROTHREEHUNDRED"
  ),
  "GQHNGFYNJAQFDMCYFPBQJKNPOXIEBCOB"
);

/*
f=(a,b,c)=>[...c].filter(b=>a.includes(b)).reduce((d,e,c)=>{if(!b)return d+e;for(let g=0;;g++)if(b[c%b.length]==a[(g+a.indexOf(e))%a.length])return d+a[g]},""); -- 160
f=(a,b,c)=>[...c].filter(b=>a.includes(b)).reduce((d,e,c)=>d+(b?a[(a.indexOf(b[c%b.length])-a.indexOf(e)+a.length)%a.length]:e),"") - 131
f=(a,b,c,z=a.length,w=c=>a.indexOf(c))=>[...c].filter(b=>a.includes(b)).reduce((d,e,c)=>d+(b?a[(w(b[c%b.length])-w(e)+z)%z]:e),"") - 130
f=(a,b,c,z=a.length,w=c=>a.indexOf(c))=>[...c].filter(b=>a.includes(b)).reduce((d,e,c)=>d+(b?a[(w(b[c%b.length])-w(e)+z)%z]:e),"") - 130
f=(a,b,c,z=a.length,w=c=>a.indexOf(c))=>[...c].filter(b=>a.includes(b)).map((d,c)=>b?a[(w(b[c%b.length])-w(d)+z)%z]:d).join("") - 127
f=(a,b,c,z=a.length,w=c=>a.indexOf(c))=>[...c].filter(a=>~w(a)).map((d,c)=>b?a[(w(b[c%b.length])-w(d)+z)%z]:d).join("") - 119
*/
f=(a,k,t,i=j=1)=>t.replace(/./g,h=>~(c=a.indexOf(h))?a[(a+a).indexOf((j+=k)[i++],c)-c]||h:"")
f=(e,f,d,i=(j=1))=>d.replace(/./g,d=>~(c=e.indexOf(d))?e[(e+e).indexOf((j+=f)[i++],c)-c]||d:"");

f = (a, k, t, i = (j = 1)) =>
  t.replace(/./g, h =>
    ~(c = a.indexOf(h)) ? a[(a + a).indexOf((j += k)[i++], c) - c] || h : ""
  );