Why do I get 'map is not a function' after an API call?
Because you assumed the data is a top-level array when it is nested inside an object. Log the full response and extract the array from the correct field before calling map on it.
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More FAQs in Common API Integration Mistakes in React Frontends
Usually because you forgot the dependency array, or because you included a state variable you update inside the effect. Each update triggers another run. Fix the dependency array with the hooks lint plugin.
Because hardcoding localhost means production calls the wrong backend. Environment variables let each environment, development and production, use the right value without code changes.
Use an AbortController. Pass its signal to fetch, and abort it in the cleanup function or when a new fetch starts. This cancels outdated requests so only the latest result is used, preventing stale data overwriting fresh data.
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