Master React Unidirectional Data Flow

Unidirectional data flow is a core React best practice where child components raise data to parents via callbacks, while parents pass data down as props. This keeps state consolidated in parent components, creating 'dumb' child components focused only on presentation. The post contrasts the correct pattern (lifting state up) with an anti-pattern using refs to access child state from a parent, visualizing how bidirectional data flow adds complexity. The conclusion notes this pattern applies to Angular and Vue as well, and includes a refactoring challenge.