React's StrictMode is sort of a helper component that helps to write better react components by wrapping a set of components with <StrictMode />. It will:
- Verify that the components inside are following some of the recommended practices and warn you if not in the console
- Verify the deprecated methods are not being used, and if they're used strict mode will warn you in the console
- Help you prevent some side effects by identifying potential risks
This is done by:
- double rendering
- React assumes that every component you write is a pure function. This means that React components you write must always return the same JSX given the same inputs (props, state, and context). If the component breaks the rule,
StrictModewill catch that
- React assumes that every component you write is a pure function. This means that React components you write must always return the same JSX given the same inputs (props, state, and context). If the component breaks the rule,
- re-running effects
- React will run one extra setup+cleanup cycle in development for every Effect to ensure it works properly
- warnings about the deprecated APIs used