In this talk, I will delve into four crit­i­cal antipat­terns that we encoun­tered in our React/TypeScript devel­op­ment process. Each sec­tion will out­line a spe­cif­ic bad prac­tice, the prob­lems it caused, and the strate­gies we employed to address it. We’ll dis­cuss the pit­falls of over­ly flex­i­ble props, the mis­use of objects in depen­den­cy arrays, the draw­backs of using array indices as keys, and the unnec­es­sary overuse of use­Ef­fect. This pre­sen­ta­tion aims to shed light on these com­mon but often over­looked mis­takes, pro­vid­ing real-world solu­tions to enhance the per­for­mance and main­tain­abil­i­ty of your applications.