perf: use Set instead of string indexOf
perf: use Set instead of string indexOf

kaicataldo/babel,hzoo/babel,kaicataldo/babel,jridgewell/babel,babel/babel,hzoo/babel,kaicataldo/babel,Skillupco/babel,babel/babel,kaicataldo/babel,jridgewell/babel,hzoo/babel,Skillupco/babel,jridgewell/babel,babel/babel,babel/babel,Skillupco/babel,hzoo/babel,jridgewell/babel,Skillupco/babel