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Legacy APIs

• Children lets you manipulate and transform the JSX received as the children prop. See alternatives.
• cloneElement lets you create a React element using another element as a starting point. See alternatives.
• Component lets you define a React component as a JavaScript class. See alternatives.
• createElement lets you create a React element. Typically, you’ll use JSX instead.
• createRef creates a ref object which can contain arbitrary value. See alternatives.
• forwardRef lets your component expose a DOM node to parent component with a ref.
• isValidElement checks whether a value is a React element. Typically used with cloneElement.
• PureComponent is similar to Component, but it skip re-renders with same props. See alternatives.

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Removed APIs

These APIs were removed in React 19:

• createFactory: use JSX instead.
• Class Components: static contextTypes: use static contextType instead.
• Class Components: static childContextTypes: use static contextType instead.
• Class Components: static getChildContext: use Context instead.
• Class Components: static propTypes: use a type system like TypeScript instead.
• Class Components: this.refs: use createRef instead.