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一、自定义Hook的应用
自定义Hook本质上只是一种函数代码逻辑的抽取#xff0c;严格意义上而言#xff0c;它并不算React的特性。 实现组件创建/销毁时打印日志 import React, { memo, useEffect, useState } from react…React 基础巩固(四十六)——自定义Hook的应用
一、自定义Hook的应用
自定义Hook本质上只是一种函数代码逻辑的抽取严格意义上而言它并不算React的特性。 实现组件创建/销毁时打印日志 import React, { memo, useEffect, useState } from react;function useLogLife(name) {useEffect(() {console.log(${name}组件创建);return () {console.log(${name}组件销毁);};}, []);
}const Home memo(() {useLogLife(Home);return h1Home Page/h1;
});const About memo(() {useLogLife(About);return h1About Page/h1;
});export default memo(function App() {const [isShow, setIsShow] useState(true);useLogLife(App);return (divh1App Component/h1button onClick{(e) setIsShow(!isShow)}切换/button{isShow Home /}{isShow About /}/div);
}); 实现Context共享 封装TokenContext和UserContext 两个Context在自定义HookuseUserToken中通过使用userUserToken同时获取两个Context的内容 import React, { memo, useContext } from react;
import { useUserToken } from ./hooks;const Home memo(() {const [user, token] useUserToken();console.log(user, token);return h1Home Page/h1;
});const About memo(() {const [user, token] useUserToken();console.log(user, token);return h1About Page/h1;
});export default memo(function App() {return (divh1App Component/h1Home /About //div);
}); 实现获取滚动位置 封装滚动监听事件 import { useEffect, useState } from react;function useScrollPosition() {const [scrollX, setScrollX] useState(0);const [scrollY, setScrollY] useState(0);useEffect(() {function handleScroll() {console.log(window.scrollX, window.scrollY);setScrollX(window.scrollX);setScrollY(window.scrollY);}window.addEventListener(scroll, handleScroll);return () {window.removeEventListener(scroll, handleScroll);};}, []);return [scrollX, scrollY];
}export default useScrollPosition; 通过useScrollPosition自定义Hook进行复用 import React, { memo } from react;
import ./style.css;
import { useScrollPosition } from ./hooks;
const Home memo(() {const [scrollX, scrollY] useScrollPosition();console.log(Home, scrollX, scrollY);return (h1Home Page: {scrollX} --- {scrollY}/h1);
});const About memo(() {const [scrollX, scrollY] useScrollPosition();console.log(About, scrollX, scrollY);return (h1About Page: {scrollX} --- {scrollY}/h1);
});
export default memo(function App() {return (div classNameapph1App Component/h1Home /About //div);
}); localStorage数据存储 封装useLocalStorage自定义Hook import { useEffect, useState } from react;function useLocalStorage(key) {const [data, setData] useState(() {const item localStorage.getItem(key);if (!item) return ;return JSON.parse(item);});useEffect(() {localStorage.setItem(key, JSON.stringify(data));}, [data]);return [data, setData];
}
export default useLocalStorage; 通过useLocalStorage来实现localStorage数据的自动化存储并进行复用。即一旦需要本地存储的值发生变化便对localStorage进行对应的更新 import React, { memo, useEffect, useState } from react;
import ./style.css;
import { useLocalStorage } from ./hooks;export default memo(function App() {// 通过key直接从localStorage获取数据const [token, setToken] useLocalStorage(token);function setTokenHandle() {setToken(new token);}const [avatarUrl, setAvatarUrl] useLocalStorage(avatarUrl);function setAvatarUrlHandle() {setAvatarUrl(new url);}return (div classNameapph1App Component/h1h1token:{token}/h1button onClick{setTokenHandle}设置token/buttonh1Avatar:{avatarUrl}/h1button onClick{setAvatarUrlHandle}设置avatarUrl/button/div);
});
