-api 설계: 어떤 주소로 들어가면 어떤 값이 반환되는지 미리 알아두자.
주소 / RESTAPI/ 서버>클라이언트 정보 /클라이언트>서버 정보
(나는 리액트 미디어 쿼리가 편한 듯하다)
yarn add react-responsive
import
import MediaQuery from 'react-responsive'
const Example = () => (
<div>
<h1>Device Test!</h1>
<MediaQuery minWidth={1224}>
<p>You are a desktop or laptop</p>
<MediaQuery minWidth={1824}>
<p>You also have a huge screen</p>
</MediaQuery>
</MediaQuery>
<MediaQuery minResolution="2dppx">
{/* You can also use a function (render prop) as a child */}
{(matches) =>
matches
? <p>You are retina</p>
: <p>You are not retina</p>
}
</MediaQuery>
</div>
)
(컴포넌트 내부2)
import { useMediaQuery } from 'react-responsive'
const Example = () => {
const isDesktopOrLaptop = useMediaQuery(
{ minDeviceWidth: 1224 },
{ deviceWidth: 1600 } // `device` prop
)
return (
<div>
{isDesktopOrLaptop &&
<p>
this will always get rendered even if device is shorter than 1224px,
that's because we overrode device settings with 'deviceWidth: 1600'.
</p>
}
</div>
)
import React from 'react'
import { useMediaQuery } from 'react-responsive'
const Example = () => {
const isDesktopOrLaptop = useMediaQuery({ minWidth: 1224 })
const isBigScreen = useMediaQuery({ minWidth: 1824 })
const isTabletOrMobile = useMediaQuery({ maxWidth: 1224 })
const isPortrait = useMediaQuery({ orientation: 'portrait' })
const isRetina = useMediaQuery({ minResolution: '2dppx' })
return (
<div>
...
</div>
)
}
const Example = () => {
const isDesktopOrLaptop = useMediaQuery(
{ minDeviceWidth: 1224 },
{ deviceWidth: 1600 } // `device` prop
)
return (
<div>
{isDesktopOrLaptop &&
<p>
this will always get rendered even if device is shorter than 1224px,
that's because we overrode device settings with 'deviceWidth: 1600'.
</p>
}
</div>
)
}
import { Context as ResponsiveContext } from 'react-responsive'
import { renderToString } from 'react-dom/server'
import App from './App'
...
// Context is just a regular React Context component, it accepts a `value` prop to be passed to consuming components
const mobileApp = renderToString(
<ResponsiveContext.Provider value={{ width: 500 }}>
<App />
</ResponsiveContext.Provider>
)
...
import React from 'react';
import AuthTemplate from '../components/auth/AuthTemplate';
import LoginForm from '../containers/auth/LoginForm';
const LoginPage = () => {
return (
<AuthTemplate>
<LoginForm />
</AuthTemplate>
);
};
export default LoginPage;
import LoginPage from './pages/LoginPage';
<Route component={PostListPage} path={['/@:username', '/']} exact />
import ReactDOM from 'react-dom';
import { BrowserRouter } from 'react-router-dom';
ReactDOM.render(
<BrowserRouter>
<App />
</BrowserRouter>,
document.getElementById('root'),
);
export default rootReducer;
import { Route, Link } from 'react-router-dom';
<Link to="/">홈</Link>
import {useMemo} from 'react
const avg = useMemo(() => getAverage(list), [list]);
(Average.js)
import React, { useState, useMemo } from 'react';
const getAverage = numbers => {
console.log('평균값 계산 중..');
if (numbers.length === 0) return 0;
const sum = numbers.reduce((a, b) => a + b);
return sum / numbers.length;
const Average = () => {
const [list, setList] = useState([]);
const [number, setNumber] = useState('');
const onChange = e => {
setNumber(e.target.value);
};
const onInsert = () => {
const nextList = list.concat(parseInt(number));
setList(nextList);
setNumber('');
};
const avg = useMemo(() => getAverage(list), [list]);
return (
<div>
<input value={number} onChange={onChange} />
<button onClick={onInsert}>등록</button>
<ul>
{list.map((value, index) => (
<li key={index}>{value}</li>
))}
</ul>
<div>
<b>평균값:</b> {avg}
</div>
</div>
);
};
export default Average;
import {useCallback} from 'react'
const onChange = useCallback(e => {
setNumber(e.target.value);
}, []);
-바뀌면 변해야 하는 함수
const onInsert = useCallback(() => {
const nextList = list.concat(parseInt(number));
setList(nextList);
setNumber('');
}, [number, list]);
(Average.js)
import React, { useState, useMemo, useCallback } from 'react';
const getAverage = numbers => {
console.log('평균값 계산 중..');
if (numbers.length === 0) return 0;
const sum = numbers.reduce((a, b) => a + b);
return sum / numbers.length;
};
const Average = () => {
const [list, setList] = useState([]);
const [number, setNumber] = useState('');
const onChange = useCallback(e => {
setNumber(e.target.value);
}, []); // 컴포넌트가 처음 렌더링될 때만 함수 생성
const onInsert = useCallback(() => {
const nextList = list.concat(parseInt(number));
setList(nextList);
setNumber('');
}, [number, list]); // number 혹은 list가 바뀌었을 때만 함수 생성
const avg = useMemo(() => getAverage(list), [list]);
return (
<div>
<input value={number} onChange={onChange} />
<button onClick={onInsert}>등록</button>
<ul>
{list.map((value, index) => (
<li key={index}>{value}</li>
))}
</ul>
<div>
<b>평균값:</b> {avg}
</div>
</div>
);
};
export default Average;
모듈 설치 필요x(react에 내장되어 있음)
마지막 모듈 export default할 때, React.memo로 감싸주기
import React from 'react';
import {
MdCheckBoxOutlineBlank,
MdCheckBox,
MdRemoveCircleOutline,
} from 'react-icons/md';
import cn from 'classnames';
import './TodoListItem.scss';
const TodoListItem = ({ todo, onRemove, onToggle }) => {
(...)
};
export default React.memo(TodoListItem);
2가지 방법: useState의 함수형 업데이트 기능 vs useReducer 사용
1번방법:
1. useState 불러오기
import {useState} from 'react'
const [number, setNumber] = useState(0);
// prevNumbers는 현재 number 값을 가리킵니다.
const onIncrease = useCallback(
() => setNumber(prevNumber => prevNumber + 1),
[],
);
<Route path="/profile/:username" component={Profile} />
const Profile = ({ match }) => {
const { username } = match.params;
const profile = data[username];
if (!profile) {
return <div>존재하지 않는 사용자입니다.</div>;
}
return (
<div>
<h3>
{username}({profile.name})
</h3>
<p>{profile.description}</p>
</div>
);
yarn add qs
<Route path="/about?details=true" component={Profile} />
import React from 'react';
import qs from 'qs';
const About = ({ location }) => {
const query = qs.parse(location.search, {
ignoreQueryPrefix: true // 이 설정을 통해 문자열 맨 앞의 ?를 생략합니다.
}));
<Route path="/about?details=true" component={Profile} />
import {withRouter} from 'react-router-dom';
import React from 'react';
import { withRouter } from 'react-router-dom';
const WithRouterSample = ({ location, match, history }) => {
return (
<div>
<h4>location</h4>
<textarea
value={JSON.stringify(location, null, 2)}
rows={7}
readOnly={true}
/>
<h4>match</h4>
<textarea
value={JSON.stringify(match, null, 2)}
rows={7}
readOnly={true}
/>
<button onClick={() => history.push('/')}>홈으로</button>
</div>
);
};
export default withRouter(WithRouterSample);
팁: JSON.stringyfy (match, null, 2) : 첫 번째 인자는 json, 두 번째 인자는 undenfined를 대체할 것, 세 번째 인자는 띄어쓰기
주의사항
현재 라우트 컴포넌트를 기준으로 라우트를 받아온다.
import {Switch} from 'react-router-dom';
<Route render={(props)=> <div> 등} ~/>
import {NavLink} from 'react-router-dom';
const Profiles = () => {
const activeStyle = {
background: 'black',
color: 'white'
};
return (
<div>
<h3>사용자 목록:</h3>
<ul>
<li>
<NavLink activeStyle={activeStyle} to="/profiles/velopert">
velopert
</NavLink>
</li>
<li>
<NavLink activeStyle={activeStyle} to="/profiles/gildong">
gildong
</NavLink>
</li>
</ul>
(...)
</div>
);
};
yarn add axios
import React, { useState } from 'react';
import axios from 'axios';
const [data, setData] = useState(null);
const onClick = async () => {
try {
const response = await axios.get(
'https://jsonplaceholder.typicode.com/todos/1',
);
setData(response.data);
} catch (e) {
console.log(e);
}
};
(return 컴포넌트 )
<button onClick={onClick}>불러오기</button>
(App.js)
import React, { useState } from 'react';
import axios from 'axios';
const App = () => {
const [data, setData] = useState(null);
const onClick = async () => {
try {
const response = await axios.get(
'https://jsonplaceholder.typicode.com/todos/1',
);
setData(response.data);
} catch (e) {
console.log(e);
}
};
return (
<div>
<div>
<button onClick={onClick}>불러오기</button>
</div>
{data && <textarea rows={7} value={JSON.stringify(data, null, 2)} readOnly={true} />}
</div>
);
};
export default App;
1.모듈 설치 & 관리할 블록 가져오기
useEffect(() => {
// async를 사용하는 함수 따로 선언
const fetchData = async () => {
setLoading(true);
try {
const response = await axios.get(
'https://newsapi.org/v2/top-headlines?country=kr&apiKey=0a8c4202385d4ec1bb93b7e277b3c51f',
);
setArticles(response.data.articles);
} catch (e) {
console.log(e);
}
setLoading(false);
};
fetchData();
}, []);
// 대기 중일 때
if (loading) {
return <NewsListBlock>대기 중...</NewsListBlock>;
}
return (
<NewsListBlock>
{articles.map(article => (
<NewsItem key={article.url} article={article} />
))}
</NewsListBlock>
);
(components/NewList.js)
import React, { useState, useEffect } from 'react';
import styled from 'styled-components';
import NewsItem from './NewsItem';
import axios from 'axios';
const NewsListBlock = styled.div`
box-sizing: border-box;
padding-bottom: 3rem;
width: 768px;
margin: 0 auto;
margin-top: 2rem;
@media screen and (max-width: 768px) {
width: 100%;
padding-left: 1rem;
padding-right: 1rem;
}
`;
const NewsList = () => {
const [articles, setArticles] = useState(null);
const [loading, setLoading] = useState(false);
useEffect(() => {
// async를 사용하는 함수 따로 선언
const fetchData = async () => {
setLoading(true);
try {
const response = await axios.get(
'https://newsapi.org/v2/top-headlines?country=kr&apiKey=0a8c4202385d4ec1bb93b7e277b3c51f',
);
setArticles(response.data.articles);
} catch (e) {
console.log(e);
}
setLoading(false);
};
fetchData();
}, []);
// 대기 중일 때
if (loading) {
return <NewsListBlock>대기 중...</NewsListBlock>;
}
// 아직 articles 값이 설정되지 않았을 때
if (!articles) {
return null;
}
// articles 값이 유효할 때
return (
<NewsListBlock>
{articles.map(article => (
<NewsItem key={article.url} article={article} />
))}
</NewsListBlock>
);
};
export default NewsList;