advent-of-code-browser-console/2020/day03.js

let d=document.body.textContent.trim().split('\n');let t=(X,Y=1)=>d.filter((l,i)=>(d[i*Y]||'')[i*X%l.length]=='#').length;[t(3),t(1)*t(3)*t(5)*t(7)*t(1,2)];