Week 12: Effects, data fetching and custom hooks

Score 4 out of 5 to complete this week.

1. 1. What is useEffect for?

   Styling componentsSyncing with things outside React, like network or timersDeclaring stateRouting
2. 2. What does an empty dependency array [] mean?

   Run on every renderRun once after the first renderNever runRun before render
3. 3. Why return a cleanup function from an effect?

   To speed up renderingTo stop timers, listeners or requests when the component unmounts or re-runsIt's requiredTo reset state
4. 4. What is a custom hook?

   A function starting with use that reuses hook logicA React pluginA CSS helperA class component
5. 5. What is the common bug when fetching in an effect without handling it?

   Fonts breakA slow old request overwrites newer resultsCSS stops workingKeys go missing