React_ts

create-react-app

npx create-react-app ts-with-react  --typescript

新建一个 Hello 组件

import React from "react";
interface IHelloProps {
  message?: string;
}
// FC=FunctionComponent
const Hello: React.FC<IHelloProps> = (props) => {
  return <h2>{props.message}</h2>;
};
Hello.defaultProps = {
  message: "Hello world!",
};
export default Hello;