如何解决React componentDidUpdate的Flow类型不兼容重写警告？

Hey there! Let's work through this TypeScript error in your React component's componentDidUpdate method. The issues are a mix of incorrect type references and a small spelling mistake—here's how to fix them:

First, let's break down the errors you're seeing: #

• ReadOnly, P, S: Could not resolve name: You're using ReadOnly<P> and ReadOnly<S> but TypeScript has no idea what P, S, or ReadOnly are here. Your component uses Props<ID_TYPE> and State as its type parameters, not generic P/S, and TypeScript's built-in readonly wrapper is spelled Readonly (lowercase 'o'), not ReadOnly.
• preContext: Incompatible override, should have type 'any': This is a follow-up error from the first issue—once you fix the type references, this will resolve itself as long as you keep _prevContext typed as any.

The Fix #

Update your componentDidUpdate signature to use your component's actual Props/State types and correct the Readonly spelling:

class EditableCell<ID_TYPE> extends React.Component<Props<ID_TYPE>, State> {
  componentDidUpdate(prevProps: Readonly<Props<ID_TYPE>>, prevState: Readonly<State>, _prevContext: any): void {
    // Your existing logic here
  }

  // Rest of your component code...
}

Even Cleaner: Let TypeScript Infer Types #

You can also skip explicit type annotations entirely—TypeScript will automatically infer the correct types for prevProps and prevState based on your component's generic parameters:

class EditableCell<ID_TYPE> extends React.Component<Props<ID_TYPE>, State> {
  componentDidUpdate(prevProps, prevState, _prevContext: any) {
    // TypeScript knows prevProps is Readonly<Props<ID_TYPE>> and prevState is Readonly<State>
  }

  // Rest of your component code...
}

Why This Works #

• Readonly<Props<ID_TYPE>> correctly references your component's props type wrapped in TypeScript's readonly utility, fixing the spelling and type reference issue.
• Using your component's actual State type instead of generic S ensures TypeScript recognizes the override as compatible with React's base Component class.
• Keeping _prevContext: any matches React's required signature for the lifecycle method.

内容的提问来源于stack exchange，提问作者Casebash