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Why do I need Keys in React Lists?

  • Lists are performant heavy and need to be used carefully.
  • Make sure every item in the list has a unique key.
  • It is preferred to not use indexes as a key unless you know for sure that the list is a static list (no additions/re-ordering/removal to the list).
  • Never use unstable keys like Math.random() to generate a key.
  • React will run into performance degradation and unexpected behavior if unstable keys are used.