2020-3.js

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f=(a,k,t,o=0,l=a.length)=>t.replace(/./g,m=>((z=a.indexOf(m))>-1?k?a[(a.indexOf(k[o++%k.length])-z+l)%l]:m:''))
f=(a,k,t,o=0,l=a.length)=>t.replace(/./g,m=>((z=a.indexOf(m))<0?'':k?a[(a.indexOf(k[o++%k.length])-z+l)%l]:m))
f=(a,k,t,o=0,l=a.length)=>t.replace(/./g,m=>(~(z=a.indexOf(m))?k?a[(a.indexOf(k[o++%k.length])-z+l)%l]:m:''))
f=(a,k,t,o=0,l=a.length)=>t.replace(/./g,m=>~(z=a.indexOf(m))?k?a[(a.indexOf(k[o++%k.length])-z+l)%l]:m:'')
f=(a,k,t,o=0,l=a.length)=>t.replace(/./g,m=>~(z=a.indexOf(m))?k?a[(a.search(k[o++%k.length])-z+l)%l]:m:'')
f=(a,k,t,o=0,r=a+a)=>t.replace(/./g,m=>~(z=a.indexOf(m))?k?r[r.indexOf(k[o++%k.length],z)-z]:m:'')
f=(a,k,t,o=0)=>t.replace(/./g,m=>~(z=a.indexOf(m))?k?a[(a+a).indexOf(k[o++%k.length],z)-z]:m:'')
f=(a,k,t,o=0)=>t.replace(/./g,m=>~(z=a.indexOf(m))?a[(a+a).indexOf(k[o++%k.length],z)-z]||m:'')
f=(a,k,t,o=w='')=>t.replace(/./g,m=>~(z=a.indexOf(m))?a[(a+a).indexOf((w+=k)[o++],z)-z]||m:'')
f=(a,k,t,o=w=1)=>t.replace(/./g,m=>~(z=a.indexOf(m))?a[(a+a).indexOf((w+=k)[o++],z)-z]||m:'')
working

submitted