react React.useState设置参数类型为数字怎么写

在 React 中，可以使用 TypeScript 或 PropTypes 为组件中的 props 和 state 设置类型。对于使用 useState Hook 设置数字类型的 state，可以这样写：

1. TypeScript：

import React, { useState } from "react";

interface Props {}

const ExampleComponent: React.FC<Props> = () => {
  const [count, setCount] = useState<number>(0);

  const handleIncrement = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={handleIncrement}>Increment</button>
    </div>
  );
};

export default ExampleComponent;

2. PropTypes：

import React, { useState } from "react";
import PropTypes from "prop-types";

const ExampleComponent = (props) => {
  const [count, setCount] = useState(0);

  const handleIncrement = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={handleIncrement}>Increment</button>
    </div>
  );
};

ExampleComponent.propTypes = {
  // other PropTypes
  count: PropTypes.number,
};

export default ExampleComponent;