{"id":2099,"date":"2022-07-24T03:53:36","date_gmt":"2022-07-23T18:53:36","guid":{"rendered":"http:\/\/www.agile-software.site\/?p=2099"},"modified":"2023-08-02T10:09:42","modified_gmt":"2023-08-02T01:09:42","slug":"%e5%88%9d%e5%bf%83%e8%80%85%e3%81%a7%e3%82%82%e7%b0%a1%e5%8d%98%e3%81%ab%e3%82%8f%e3%81%8b%e3%82%8breact-useeffect-uselayouteffect%e3%81%ae%e4%bd%bf%e3%81%84%e6%96%b9","status":"publish","type":"post","link":"https:\/\/agile-software.net\/?p=2099","title":{"rendered":"\u521d\u5fc3\u8005\u3067\u3082\u7c21\u5358\u306b\u308f\u304b\u308bReact useEffect, useLayoutEffect\u306e\u4f7f\u3044\u65b9"},"content":{"rendered":"\n

React\u306eHook\u306e\u4e2d\u3067\u3082useState\u306e\u6b21\u306b\u4f7f\u7528\u983b\u5ea6\u3082\u9ad8\u304f\u91cd\u8981\u306auseEffect\u306e\u4f7f\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8aac\u660e\u3092\u884c\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n

\u30b7\u30f3\u30d7\u30eb\u306a\u30b3\u30fc\u30c9\u3092\u5229\u7528\u3057\u3066\u3044\u308b\u306e\u3067\u672c\u6587\u66f8\u3092\u8aad\u307f\u7d42\u3048\u308b\u3068useEffect\u306e\u57fa\u672c\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u3068useEffect\u3092\u5229\u7528\u3057\u305f\u5916\u90e8\u304b\u3089\u306e\u30c7\u30fc\u30bf\u53d6\u5f97\u65b9\u6cd5\u3001\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u3068\u306e\u95a2\u4fc2\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u307e\u305fuseEffect\u3068\u975e\u5e38\u306b\u3088\u304f\u4f3c\u305f\u6a5f\u80fd\u3092\u6301\u3064useLayoutEffect\u3068\u306e\u9055\u3044\u3082\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n

useEffect\u306e\u52d5\u4f5c\u78ba\u8a8d\u306e\u305f\u3081\u306bReack Hook\u306euseState\u3092\u5229\u7528\u3059\u308b\u306e\u3067useState\u306e\u77e5\u8b58\u304c\u5fc5\u8981\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n

React useEffect\u3068\u306f<\/h2>\n\n\n\n

useEffect\u306fFunctional\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u307f\u3067\u5229\u7528\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u308bHook\u3067\u3059\u3002useEffect\u306eEffect\u306f\u201dSide Effect\u201d(\u526f\u4f5c\u7528)\u3092\u610f\u5473\u3057\u3066\u3044\u307e\u3059\u3002Side Effect\u306b\u306ffetch\u95a2\u6570\u3092\u5229\u7528\u3057\u3066\u5916\u90e8\u306e\u30ea\u30bd\u30fc\u30b9\u304b\u3089\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3057\u305f\u308a\u3001DOM\u306e\u66f4\u65b0\u3001\u30ed\u30ae\u30f3\u30b0(console.log\u3082\u542b\u3080)\u306a\u3069\u306e\u51e6\u7406\u304c\u542b\u307e\u308c\u307e\u3059\u3002<\/p>\n\n\n\n

useEffect\u3092\u7406\u89e3\u3059\u308b\u4e0a\u3067class\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306b\u95a2\u3059\u308b\u6a5f\u80fd\u3068\u306e\u6bd4\u8f03\u306f\u91cd\u8981\u3067\u306f\u306a\u3044\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u304c\u3001useEffect\u306fReact Class\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30ebcomponentDidMount, componentDidUpdate\u3068componentWillUnmount\u306e3\u3064\u3068\u540c\u69d8\u306a\u51e6\u7406\u3092\u884c\u3046\u3053\u3068\u304c\u3067\u304d\u308bHook\u3067\u3059\u3002<\/p>\n\n\n\n

componetDidMount\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30de\u30a6\u30f3\u30c8\u76f4\u5f8c\u306b\u5b9f\u884c\u3055\u308c\u3001componentDidUpdate\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u518d\u63cf\u5199\u3055\u308c\u308b\u5ea6\u306b\u5b9f\u884c\u3055\u308c\u3001comonentWillUnmount\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3055\u308c\u3066\u7834\u68c4\u3055\u308c\u308b\u76f4\u524d\u306b\u5b9f\u884c\u3055\u308c\u308b\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u30d5\u30c3\u30af\u3067\u3059\u3002<\/p>\n\n\n\n

\u6700\u8fd1React\u3092\u52c9\u5f37\u3057\u59cb\u3081\u305f\u4eba\u306e\u5834\u5408\u3001React Class\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092\u5229\u7528\u305b\u305aFunctional\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u307f\u3067\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3092\u958b\u767a\u3067\u304d\u308b\u305f\u3081Classs\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306b\u3064\u3044\u3066\u8aac\u660e\u3092\u884c\u3063\u3066\u3082\u308f\u304b\u3089\u306a\u3044\u3068\u601d\u3044\u307e\u3059\u3002\u305d\u306e\u5834\u5408\u306fClass\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3068\u306e\u6bd4\u8f03\u306f\u7121\u8996\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u3057\u304b\u3057\u3001\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u30d5\u30c3\u30af\u306b\u3064\u3051\u3089\u308c\u3066\u3044\u308b\u540d\u524dcomponentDidMount\u306a\u3069\u306fuseEffect\u3068\u306f\u7570\u306a\u308a\u540d\u524d\u304b\u3089\u3069\u306e\u3088\u3046\u306a\u51e6\u7406\u304b\u30a4\u30e1\u30fc\u30b8\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u306e\u3067useEffect\u306e\u7406\u89e3\u306e\u52a9\u3051\u306b\u306f\u306a\u308b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n\n\n\n

useEffect\u3092\u5229\u7528\u3059\u308b\u3053\u3068\u3067\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u5185\u5bb9\u3092\u8868\u793a\u3059\u308b\u969b\u306b\u5916\u90e8\u306e\u30b5\u30fc\u30d0\u304b\u3089API\u3092\u7d4c\u7531\u3057\u3066\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3059\u308b\u3053\u3068\u3084\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u66f4\u65b0\u3059\u308b\u5ea6\u306b\u5225\u306e\u51e6\u7406\u3092\u5b9f\u884c\u3059\u308b\u3068\u3044\u3046\u3053\u3068\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002\u307e\u305fuseEffect\u306f\u4e00\u3064\u306e\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306b\u8907\u6570\u8a18\u8ff0\u3059\u308b\u3053\u3068\u3082\u53ef\u80fd\u3067\u3059\u3002<\/p>\n\n\n\n

\u305d\u3082\u305d\u3082\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u3063\u3066\u4f55\uff1f\u3068\u3044\u3046\u4eba\u3067\u3082\u308f\u304b\u308b\u3088\u3046\u306b\u30b7\u30f3\u30d7\u30eb\u306a\u4f8b\u3092\u4f7f\u3063\u3066useEffect\u306e\u4f7f\u7528\u65b9\u6cd5\u3092\u78ba\u8a8d\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n

useEffect\u306f\u753b\u9762\u304c\u63cf\u5199\u3055\u308c\u305f\u5f8c\u306b\u5b9f\u884c\u3055\u308c\u308b\u3068\u3044\u3046\u3053\u3068\u304c\u91cd\u8981\u306a\u306e\u3067\u305d\u308c\u3082\u3057\u3063\u304b\u308a\u3068\u899a\u3048\u3066\u304a\u3044\u3066\u304f\u3060\u3055\u3044\u3002\u63cf\u5199\u524d\u306b\u4f55\u304b\u51e6\u7406\u3092\u3057\u305f\u3044\u3068\u3044\u3046\u6642\u306b\u5229\u7528\u3059\u308b\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002\u63cf\u5199\u524d\u306b\u4f55\u304b\u51e6\u7406\u3092\u884c\u3044\u305f\u3044\u3068\u3044\u3046\u5834\u5408\u306b\u306fuseLayoutEffect Hook\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n

\u6e96\u5099<\/h2>\n\n\n\n

useEffect\u306e\u52d5\u4f5c\u78ba\u8a8d\u3092\u884c\u3046\u305f\u3081\u306b\u305d\u306e\u30d9\u30fc\u30b9\u306b\u306a\u308b\u30b3\u30fc\u30c9\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002<\/p>\n\n\n\n

useState\u3092\u4f7f\u3063\u3066count\u306estate\u5909\u6570\u3092\u8a2d\u5b9a\u3057\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u5ea6\u306bCount\u6570\u304c\u5897\u3048\u308b\u30b3\u30fc\u30c9\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002<\/p>\n\n\n\n

\nimport React,{ useState} from 'react';\nimport '.\/App.css';\n\nfunction App() {\n\n  const [count, setCount] = useState(0)\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <h2>Count: { count }<\/h2>\n      <button onClick={() => setCount(count+1)}>+<\/button>\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u4f5c\u6210\u5f8c\u3001\u30d6\u30e9\u30a6\u30b6\u3092\u958b\u304f\u3068Count\u306e\u521d\u671f\u5024\u306f0\u3067\u3059\u304c\u8868\u793a\u3055\u308c\u3066\u3044\u308b+\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3068Count\u6570\u304c\u5897\u3048\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\"Count\u6570\u304c\u5897\u3048\u308b\u3053\u3068\u3092\u78ba\u8a8d\"
Count\u6570\u304c\u5897\u3048\u308b\u3053\u3068\u3092\u78ba\u8a8d<\/figcaption><\/figure>\n\n\n\n
useEffect\u306e\u52d5\u4f5c\u78ba\u8a8d<\/h2>\n\n\n\n
\u3053\u306e\u6642\u70b9\u3067useEffect\u304c\u3069\u306e\u3088\u3046\u306a\u3082\u306e\u304b\u308f\u304b\u3089\u306a\u304f\u3066\u3082\u5b89\u5fc3\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u3053\u3053\u304b\u3089\u4f7f\u3044\u65b9\u3092\u8aac\u660e\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u521d\u3081\u3066\u306euseEffect<\/h3>\n\n\n\n
useEffect\u3092\u5229\u7528\u3059\u308b\u5834\u5408\u306f\u3001useState\u3068\u540c\u69d8\u306buseEffect\u3092import\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002useEffect\u3092\u5229\u7528\u3057\u3066\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306b\u6587\u5b57\u5217\u3092\u8868\u793a\u3059\u308b\u3088\u3046\u306b\u5148\u7a0b\u306e\u30b3\u30fc\u30c9\u306e\u66f4\u65b0\u3092\u884c\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState, useEffect } from 'react';\nimport '.\/App.css';\n\nfunction App() {\n\n  const [count, setCount] = useState(0)\n\n  useEffect(()=>{\n    console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n  })\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <h2>Count: { count }<\/h2>\n      <button onClick={() => setCount(count+1)}>+<\/button>\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
console.log\u306e\u4e2d\u8eab\u3092\u78ba\u8a8d\u3059\u308b\u305f\u3081\u306b\u30d6\u30e9\u30a6\u30b6\u306e\u30c7\u30d9\u30ed\u30c3\u30d1\u30fc\u30c4\u30fc\u30eb\u3092\u958b\u3044\u3066\u304f\u3060\u3055\u3044\u3002useEffect\u306e\u4e2d\u306bconsole.log\u3092\u8ffd\u52a0\u3057\u30d6\u30e9\u30a6\u30b6\u3092\u30ea\u30ed\u30fc\u30c9\u3059\u308b\u3053\u3068\u3067\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306buseEffect\u306econsole.log\u306e\u4e2d\u3067\u8a18\u8ff0\u3057\u305f\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\"useEffect\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8\"
useEffect\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8<\/figcaption><\/figure>\n\n\n\n
useEffect\u3092\u8ffd\u52a0\u3057\u307e\u3057\u305f\u304c\u3001useEffect\u3092\u5b9f\u884c\u3055\u305b\u308b\u3088\u3046\u306a\u51e6\u7406\u3092\u30b3\u30fc\u30c9\u306b\u8a18\u8ff0\u3057\u3066\u3044\u306a\u3044\u306e\u3067useEffect\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u8868\u793a\u3055\u308c\u308b\u6d41\u308c\u306e\u4e2d\u3067\u81ea\u52d5\u3067\u5b9f\u884c\u3055\u308c\u3066\u3044\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u304b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\u6b21\u306b+\u30dc\u30bf\u30f3\u30923\u56de\u30af\u30ea\u30c3\u30af\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u306fCount\u306e\u6570\u304c3\u306b\u306a\u308a\u3001\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u3092\u898b\u308b\u3068\u201duseEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f\u201d\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u304c4\u306b\u306a\u3063\u3066\u3044\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\"\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306e\u78ba\u8a8d\"
\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306e\u78ba\u8a8d<\/figcaption><\/figure>\n\n\n\n
\u3053\u3053\u307e\u3067\u306e\u52d5\u4f5c\u78ba\u8a8d\u3067\u3001useEffect\u306f\u30d6\u30e9\u30a6\u30b6\u3067\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u521d\u3081\u3066\u8868\u793a\u3055\u308c\u308b\u6642\u306b\u5fc5\u305a\u4e00\u5ea6\u5b9f\u884c\u3055\u308c\u308b\u3053\u3068\u3001Count\u306e\u66f4\u65b0\u306b\u3088\u308a\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u66f4\u65b0\u3055\u308c\u308b\u5ea6\u306b\u5b9f\u884c<\/strong>\u3055\u308c\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
useState\u3067\u5024\u306e\u66f4\u65b0\u304c\u884c\u308f\u308c\u308b\u3068\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306f\u305d\u306e\u5024\u3092\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u3082\u66f4\u65b0\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u305f\u3081\u518d\u63cf\u5199(\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0)\u304c\u884c\u308f\u308c\u307e\u3059\u3002props\u304c\u66f4\u65b0\u3055\u308c\u305f\u5834\u5408\u3082\u540c\u3058\u3088\u3046\u306b\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u518d\u63cf\u5199\u304c\u884c\u308f\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
useEffect\u304c\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u521d\u671f\u5316\u4e2d\u306b\u5fc5\u305a\u4e00\u5ea6\u5b9f\u884c\u3055\u308c\u308b\u3068\u3044\u3046\u3053\u3068\u306fuseEffect\u3092\u5229\u7528\u3057\u3066\u4e8b\u524d\u306b\u5916\u90e8\u304b\u3089API\u3067\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3059\u308b\u3053\u3068\u3067\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u521d\u671f\u5316\u306e\u6d41\u308c\u306e\u4e2d\u3067\u30c7\u30fc\u30bf\u3092\u8868\u793a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u3064\u307e\u308a\u30da\u30fc\u30b8\u3092\u958b\u3044\u305f\u76f4\u5f8c\u306b\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3057\u305f\u308a\u4f55\u304b\u306e\u64cd\u4f5c\u3092\u3059\u308b\u3053\u3068\u306a\u3057\u3067\u5916\u90e8\u304b\u3089\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u3092\u8868\u793a\u3059\u308b\u3053\u3068\u3067\u304d\u307e\u3059\u3002useEffect\u3092\u5229\u7528\u3057\u305f\u30c7\u30fc\u30bf\u306e\u53d6\u5f97\u65b9\u6cd5\u3068\u8868\u793a\u65b9\u6cd5\u306b\u3064\u3044\u3066\u306f\u5f8c\u307b\u3069\u5b9f\u969b\u306e\u30b3\u30fc\u30c9\u3092\u4f7f\u3063\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\u6700\u521d\u306e1\u56de\u306e\u8868\u793a\u76f4\u5f8c\u306b\u884c\u308f\u308c\u308buseEffect\u306e\u5b9f\u884c\u304c\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u306ecomponentDidMount\u306b\u5bfe\u5fdc\u3057\u3001\u305d\u308c\u4ee5\u964d\u306euseEffect\u306e\u5b9f\u884c\u306fcomponentDidUpdate\u306b\u5bfe\u5fdc\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0\u306b\u3088\u308buseEffect\u306e\u505c\u6b62<\/h3>\n\n\n\n
useEffect\u306f\u5fc5\u305a\u4e00\u5ea6\u4f55\u3082\u3057\u306a\u304f\u3066\u3082\u5b9f\u884c\u3055\u308c\u308b\u3053\u3068\u3068\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u66f4\u65b0\u3055\u308c\u308b\u5ea6\u306buseEffect\u304c\u5b9f\u884c\u3055\u308c\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3057\u305f\u3002\u3057\u304b\u3057\u3001\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0\u306e\u5ea6\u306buseEffect\u306e\u4e2d\u306e\u51e6\u7406\u304c\u5fc5\u8981\u3067\u306f\u306a\u3044\u5834\u5408\u3082\u3042\u308a\u307e\u3059\u3002\u305d\u306e\u3088\u3046\u306a\u5834\u5408\u306f\u3001\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0\u306b\u3088\u308buseEffect\u3092\u6b62\u3081\u308b\u3053\u3068\u304c\u53ef\u80fd\u3067\u3059\u3002\u305d\u306e\u5834\u5408\u306fuseEffect\u306e\u7b2c2\u5f15\u6570\u306b[]\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/strong><\/p>\n\n\n\n
\nuseEffect(()=>{\n  console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n},[])\n<\/code><\/pre>\n\n\n\n
[]\u3092\u8ffd\u52a0\u5f8c\u306b\u30d6\u30e9\u30a6\u30b6\u3092\u4f7f\u3063\u3066+\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3057\u3066Count\u6570\u3092\u5897\u3084\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u8868\u793a\u3055\u308c\u308b\u6700\u521d\u306e\u4e00\u56de\u306euseEffect\u306f\u5b9f\u884c\u3055\u308c\u307e\u3059\u304c\u3001\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3057\u3066\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092\u66f4\u65b0\u3057\u3066\u3082useEffect\u306f\u5b9f\u884c\u3055\u308c\u306a\u304f\u306a\u308a\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
\"useEffect\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8\"
useEffect\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8<\/figcaption><\/figure>\n\n\n\n
state\u5909\u6570\u306b\u3088\u308buseEffect\u306e\u5b9f\u884c<\/h3>\n\n\n\n
useEffect\u306b\u7a7a\u306e\u914d\u5217\u3092\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u3067\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0\u306b\u3088\u308buseEffect\u306e\u5b9f\u884c\u3092\u6b62\u3081\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3057\u305f\u3002\u3057\u304b\u3057\u5834\u5408\u306b\u3088\u3063\u3066\u306f\u3042\u308b\u7279\u5b9a\u306estate\u5909\u6570\u306e\u66f4\u65b0\u304c\u3042\u3063\u305f\u6642\u3060\u3051useEffect\u3092\u5b9f\u884c\u3057\u305f\u3044\u3068\u3044\u3046\u5834\u5408\u304c\u3042\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002\u305d\u306e\u5834\u5408\u306f\u8ffd\u52a0\u3057\u305f\u7a7a\u306e\u914d\u5217\u306bstate\u5909\u6570\u3092\u8ffd\u52a0\u3059\u308b\u3053\u3068\u3067\u305d\u306e\u5909\u6570\u306e\u5909\u5316\u306e\u307f\u3092\u76e3\u8996\u3057useEffect\u3092\u5b9f\u884c\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u52d5\u4f5c\u78ba\u8a8d\u3092\u884c\u3046\u305f\u3081\u306b\u65b0\u305f\u306bstate\u5909\u6570count2\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002useEffect\u306e\u914d\u5217\u306b\u306fcount\u3060\u3051\u3092\u8ffd\u52a0\u3057\u3066\u3044\u307e\u3059\u3002\u3064\u307e\u308acount\u3060\u3051\u3092\u76e3\u8996\u3057\u3001\u3053\u306e\u5909\u6570\u304c\u66f4\u65b0\u3055\u308c\u308b\u3068useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState, useEffect} from 'react';\nimport '.\/App.css';\n\nfunction App() {\n\n  const [count, setCount] = useState(0)\n  const [count2, setCount2] = useState(0)\n\n  useEffect(()=>{\n    console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n  },[count])\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <h2>Count: { count }\/ Count2: { count2 }<\/h2>\n      <button onClick={() => setCount(count+1)}>Count+<\/button><br\/>\n      <button onClick={() => setCount2(count2+1)}>Count2+<\/button><br\/>\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u30d6\u30e9\u30a6\u30b6\u3092\u958b\u3044\u3066Count+\u30dc\u30bf\u30f3\u30923\u56de\u3001Count2+\u30dc\u30bf\u30f3\u30925\u56de\u30af\u30ea\u30c3\u30af\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\"\u8ffd\u52a0\u3057\u305fCount2\"
\u8ffd\u52a0\u3057\u305fCount2<\/figcaption><\/figure>\n\n\n\n
Count\u30dc\u30bf\u30f3\u3092\u62bc\u3059\u6642\u306e\u307fuseEffect\u304c\u5b9f\u884c\u3055\u308c\u308b\u306e\u3067\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306b\u306f4\u56de\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\"count\u66f4\u65b0\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8\u56de\u6570\"
count\u66f4\u65b0\u306b\u3088\u308b\u30e1\u30c3\u30bb\u30fc\u30b8\u56de\u6570<\/figcaption><\/figure>\n\n\n\n
\u6700\u521d\u306e1\u56de\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u8868\u793a\u3055\u308c\u308b\u969b\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u306e\u305f\u30814\u56de\u3068\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
useEffect\u306e[]\u914d\u5217\u306e\u5229\u7528\u65b9\u6cd5\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
useEffect\u5185\u3067count\u6570\u3092\u5897\u3084\u3057\u305f\u5834\u5408\u306e\u52d5\u4f5c<\/h3>\n\n\n\n
setCount, setCount2\u3092\u4f7f\u3063\u3066useEffect\u5185\u3067count\u6570\u3092\u5897\u3084\u3059\u3068\u3069\u306e\u3088\u3046\u306a\u52d5\u4f5c\u306b\u306a\u308b\u306e\u304b\u78ba\u8a8d\u3057\u3066\u304a\u304d\u307e\u3057\u3087\u3046\u3002<\/p>\n\n\n\n
\nuseEffect(()=>{\n  console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n  setCount(count+1)\n  setCount2(count2+1)\n},[count])\n<\/code><\/pre>\n\n\n\n
count\u306e\u307f\u914d\u5217\u306b\u8ffd\u52a0\u3057\u3066\u304a\u3044\u3066\u3082\u3069\u3061\u3089\u306estate\u5909\u6570\u3082\u5897\u52a0\u3057\u7d9a\u3051\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3059\u3002\u3053\u306e\u5834\u5408\u306fcount\u3068\u3044\u3046\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u8868\u793a\u3057\u3066\u3044\u308b\u5024\u306e\u305f\u3081useEffect\u304c\u52d5\u4f5c\u3057\u7d9a\u3051\u3066\u3044\u308b\u3053\u3068\u3092\u76ee\u8996\u3067\u78ba\u8a8d\u3067\u304d\u308b\u305f\u3081\u4e88\u60f3\u5916\u306e\u51e6\u7406\u304b\u3069\u3046\u304b\u3059\u3050\u306b\u5224\u65ad\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u306f\u8868\u793a\u3055\u308c\u306a\u3044Fetch\u306a\u3069\u306e\u51e6\u7406\u306e\u5834\u5408\u306b\u306f\u9069\u5207\u306b[]\u306e\u8a2d\u5b9a\u3092\u884c\u308f\u306a\u3044\u3068useEffect\u304c\u30d0\u30c3\u30af\u30b0\u30e9\u30f3\u30c9\u3067\u52d5\u4f5c\u3057\u7d9a\u3051\u308b\u3068\u3044\u3046\u554f\u984c\u304c\u767a\u751f\u3057\u307e\u3059\u3002useEffect\u3092\u5229\u7528\u3059\u308b\u5834\u5408\u306f[]\u306e\u8a2d\u5b9a\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n\n\n\n
\"useEffect\u5185\u3067count\u3092\u5897\u3084\u3059\"
useEffect\u5185\u3067count\u3092\u5897\u3084\u3059<\/figcaption><\/figure>\n\n\n\n
useEffect\u3067\u306e\u5916\u90e8\u304b\u3089\u30c7\u30fc\u30bf\u3092fetch\u3059\u308b\u65b9\u6cd5<\/h3>\n\n\n\n
useEffect\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u521d\u671f\u5316\u4e2d\u306e\u30de\u30a6\u30f3\u30c8\u5f8c\u306b\u5916\u90e8\u304b\u3089\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3059\u308b\u969b\u306b\u5229\u7528\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u5b9f\u969b\u306b\u5916\u90e8\u306e\u30b5\u30fc\u30d0\u3092\u5229\u7528\u3057\u3066\u3069\u306e\u3088\u3046\u306b\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3059\u308b\u305f\u3081\u306b\u8a2d\u5b9a\u3092\u884c\u3046\u306e\u304b\u78ba\u8a8d\u3092\u3057\u3066\u304a\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u5916\u90e8\u306e\u30ea\u30bd\u30fc\u30b9\u306f\u3001JSONPLACEHOLDER<\/a>\u3092\u5229\u7528\u3057\u3066fetch\u30e1\u30bd\u30c3\u30c9\u3067posts\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3057\u307e\u3059\u3002JSONPlaceHolder\u306f\u6307\u5b9a\u3057\u305fURL\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u3068\u30c0\u30df\u30fc\u306eJSON\u30c7\u30fc\u30bf\u3092\u623b\u3057\u3066\u304f\u308c\u308b\u30b5\u30fc\u30d3\u30b9\u3067\u7121\u6599\u3067\u5229\u7528\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u5916\u90e8\u306e\u30b5\u30fc\u30d0\u306e\u3084\u308a\u3068\u308a\u306buseEffect\u3092\u5229\u7528\u3059\u308b\u5834\u5408\u306f\u7b2c2\u5f15\u6570\u306b[](\u914d\u5217)\u3092\u3064\u3051\u308b\u306e\u3092\u5fd8\u308c\u306a\u3044\u3067\u304f\u3060\u3055\u3044\u3002\u914d\u5217\u3092\u3064\u3051\u3066\u3044\u306a\u3044\u5834\u5408\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u66f4\u65b0\u306b\u3088\u308auseEffect\u304c\u5b9f\u884c\u3055\u308c\u3001\u30b5\u30fc\u30d0\u3078\u306eFetch\u304c\u7d99\u7d9a\u3057\u3066\u884c\u308f\u308c\u308b\u3053\u3068\u306b\u306a\u308a\u30b5\u30fc\u30d0\u3078\u306e\u8ca0\u8377\u3092\u304b\u3051\u308b\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u51e6\u7406\u304c\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u306f\u6c17\u3065\u304b\u306a\u3044\u5834\u5408\u304c\u3042\u308b\u306e\u3067\u30d6\u30e9\u30a6\u30b6\u4e0a\u3067\u306f\u306a\u306b\u3082\u767a\u751f\u3057\u3066\u3044\u306a\u3044\u306e\u306b\u3059\u3054\u3044\u6570\u306e\u30ea\u30af\u30a8\u30b9\u30c8\u304c\u30b5\u30fc\u30d0\u306b\u9001\u4fe1\u3055\u308c\u3066\u3044\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState, useEffect} from 'react';\nimport '.\/App.css';\n\nfunction App() {\n\n  const [posts, setPosts] = useState([]);\n\n  useEffect(() => {\n    fetch('https:\/\/jsonplaceholder.typicode.com\/posts')\n      .then(response => response.json())\n      .then(data => {\n        setPosts(data)\n      },[])\n  })\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <div>\n        {\n          posts.map(post => (\n            <div key={post.id}>{post.title}<\/div>\n          ))\n        }\n      <\/div>\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
useState\u3092\u4f7f\u3063\u3066stata\u5909\u6570posts\u3092\u5b9a\u7fa9\u3057\u3001\u521d\u671f\u5024\u3092\u7a7a\u306e\u914d\u5217\u306b\u8a2d\u5b9a\u3057\u307e\u3059\u3002\u30de\u30a6\u30f3\u30c8\u5f8c\u306buseEffect\u5185\u306efetch\u30e1\u30bd\u30c3\u30c9\u304c\u5b9f\u884c\u3055\u308c\u3001JSONPLACEHOLDER\u306eURL\u306b\u30a2\u30af\u30bb\u30b9\u3092\u884c\u3044posts\u30c7\u30fc\u30bf\u4e00\u89a7\u3092\u53d6\u5f97\u3057\u307e\u3059\u3002\u53d6\u5f97\u3057\u305f\u30c7\u30fc\u30bf\u306fsetPost\u3067posts\u5909\u6570\u306b\u633f\u5165\u3057\u307e\u3059\u3002\u6700\u5f8c\u306bmap\u30e1\u30bd\u30c3\u30c9\u3067\u5c55\u958b\u3057\u3001\u30d6\u30e9\u30a6\u30b6\u306b\u4e00\u89a7\u3092\u8868\u793a\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
useEffect\u3092\u5229\u7528\u3059\u308b\u3068\u5916\u90e8\u304b\u3089\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3057\u8868\u793a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
\"post\u306e\u30ea\u30b9\u30c8\u4e00\u89a7\"
post\u306e\u30ea\u30b9\u30c8\u4e00\u89a7<\/figcaption><\/figure>\n\n\n\n
async, await\u3092\u5229\u7528\u3057\u3066\u5916\u90e8\u304b\u3089\u53d6\u5f97\u3059\u308b\u5834\u5408<\/h3>\n\n\n\n
useEffect\u3067async, await\u3092\u5229\u7528\u3057\u3066\u5916\u90e8\u30ea\u30bd\u30fc\u30b9\u304b\u3089\u30c7\u30fc\u30bf\u3092\u53d6\u5f97\u3057\u305f\u3044\u5834\u5408\u306f\u4e0b\u8a18\u306e\u3088\u3046\u306b\u8a18\u8ff0\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u8868\u793a\u3055\u308c\u308b\u5185\u5bb9\u306f\u5148\u307b\u3069\u3068\u540c\u3058\u3067\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState, useEffect} from 'react';\nimport '.\/App.css';\n\nfunction App() {\n\n  const [posts, setPosts] = useState([]);\n\n  useEffect(() => {\n    const fetchPost = async () => {\n      const response = await fetch(\n        'https:\/\/jsonplaceholder.typicode.com\/posts'\n      );\n      const posts = await response.json();\n      setPosts(posts);\n    };\n    fetchPost();\n  })\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <div>\n        {\n          posts.map(post => (\n            <div key={post.id}>{post.title}<\/div>\n          ))\n        }\n      <\/div>\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u6642\u306e\u51e6\u7406<\/h2>\n\n\n\n
\u3053\u3053\u307e\u3067\u306e\u52d5\u4f5c\u78ba\u8a8d\u3067\u3001useEffect\u3067\u306f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30e9\u30a4\u30d5\u30b5\u30a4\u30af\u30eb\u306e\u6d41\u308c\u306e\u4e2d\u3067\u81ea\u52d5\u3067\u5b9f\u884c\u3055\u308c\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u3001componentDidMount, componentDidUpdate\u3068\u540c\u69d8\u306e\u51e6\u7406\u304c\u884c\u3048\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
\u6700\u5f8c\u306b\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u6642\u306b\u5b9f\u884c\u3055\u308c\u308bcomponentWillUnmount\u3068\u540c\u69d8\u306e\u51e6\u7406\u306b\u3064\u3044\u3066\u8aac\u660e\u3092\u884c\u306a\u3063\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\u65b0\u3057\u3044\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8Count.js\u306e\u4f5c\u6210<\/h3>\n\n\n\n
\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u6642\u306b\u884c\u3046\u51e6\u7406\u306e\u52d5\u4f5c\u78ba\u8a8d\u3092\u884c\u3046\u305f\u3081\u306b\u65b0\u305f\u306bCount\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002\u30d5\u30a1\u30a4\u30eb\u306fcomponents\u30c7\u30a3\u30ec\u30af\u30c8\u30ea\u306e\u4e0b\u306bCount.js\u30d5\u30a1\u30a4\u30eb\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\u4e2d\u8eab\u306fuseState\u3067state\u5909\u6570count\u3092\u8ffd\u52a0\u3057\u3001useEffect\u3067\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u30de\u30a6\u30f3\u30c8\u5f8c\u306bsetInterval\u3092\u4f7f\u3063\u30661\u79d2\u3054\u3068\u306bcount\u30921\u3064\u30a2\u30c3\u30d7\u3059\u308b\u3068\u3044\u3063\u305f\u3082\u306e\u3067\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useEffect, useState } from 'react';\n\nfunction Count() {\n\n    const [count, setCount] = useState(0)\n\n    useEffect(() => {\n        console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n\n        setInterval(() => {\n            setCount(count => count + 1);\n            console.log('\u30ab\u30a6\u30f3\u30c8\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3057\u305f')\n          }, 1000);\n\n    },[])\n\n    return (\n      <div>\n          <h1>Count: {count}<\/h1>\n      <\/div>\n    );\n  }\n  \n  export default Count;\n<\/code><\/pre>\n\n\n\n
\u30e1\u30a4\u30f3\u306eApp.js\u30d5\u30a1\u30a4\u30eb\u304b\u3089Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092import\u3057\u3066\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState } from 'react';\nimport '.\/App.css';\nimport Count from '.\/components\/Count.js'\n\nfunction App() {\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <Count\/>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u30d6\u30e9\u30a6\u30b6\u3067\u78ba\u8a8d\u3059\u308b\u3068SetInterval\u3092\u8a2d\u5b9a\u3057\u3066\u3044\u308b\u306e\u3067\u30011\u79d2\u3054\u3068\u306bCount\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\"Count\u304c1\u79d2\u3054\u3068\u306b\u30a2\u30c3\u30d7\"
Count\u304c1\u79d2\u3054\u3068\u306b\u30a2\u30c3\u30d7<\/figcaption><\/figure>\n\n\n\n
useEffect\u306f\u4e00\u5ea6\u3060\u3051\u5b9f\u884c\u3055\u308c\u3001\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306b\u306fCount\u304c\u5897\u3048\u308b\u5ea6\u306b\u201d\u30ab\u30a6\u30f3\u30c8\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3057\u305f\u201d\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\"\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306e\u8868\u793a\"
\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306e\u8868\u793a<\/figcaption><\/figure>\n\n\n\n
\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u51e6\u7406\u306e\u8ffd\u52a0<\/h3>\n\n\n\n
Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3059\u308b\u969b\u306e\u51e6\u7406\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002useEffect\u306e\u4e2d\u306breturn\u3092\u8ffd\u52a0\u3057\u51e6\u7406\u3092\u8a2d\u5b9a\u3059\u308b\u3053\u3068\u3067\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u6642\u306b\u305d\u306e\u51e6\u7406\u304c\u884c\u308f\u308c\u307e\u3059\u3002\u3053\u3053\u3067\u306fconsole.log\u3067\u30e1\u30c3\u30bb\u30fc\u30b8\u3092\u8868\u793a\u3055\u305b\u307e\u3059\u3002<\/p>\n\n\n\n
\nuseEffect(() => {\n    console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n\n    setInterval(() => {\n        setCount(count => count + 1);\n        console.log('\u30ab\u30a6\u30f3\u30c8\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3057\u305f')\n        }, 1000);\n\n    return () => {\n        console.log('\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3057\u307e\u3057\u305f')\n    }\n},[])\n<\/code><\/pre>\n\n\n\n
\u3053\u3053\u307e\u3067\u306e\u8a2d\u5b9a\u3067\u306f\u3001\u30d6\u30e9\u30a6\u30b6\u3092\u30ea\u30ed\u30fc\u30c9\u3057\u3066\u3082\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u51e6\u7406\u6642\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u3092\u8868\u793a\u3055\u305b\u308b\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u306e\u51e6\u7406\u3092\u78ba\u8a8d\u3059\u308b\u305f\u3081\u306b\u89aa\u5074\u306eApp.js\u3092\u5229\u7528\u3057\u3066\u3001Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u8868\u793a\/\u975e\u8868\u793a\u3092\u5236\u5fa1\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
Toggle\u51e6\u7406\u306e\u8ffd\u52a0<\/h3>\n\n\n\n
Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u8868\u793a\/\u975e\u8868\u793a\u3092\u5207\u308a\u66ff\u3048\u308b\u305f\u3081\u306bApp.js\u30d5\u30a1\u30a4\u30eb\u306buseState\u3067state\u5909\u6570display\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002\u307e\u305fToggle\u30dc\u30bf\u30f3\u3092\u8ffd\u52a0\u3057\u3001onClick\u30a4\u30d9\u30f3\u30c8\u3067display\u5909\u6570\u306e\u5024\u3092\u5207\u308a\u66ff\u3048\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport React,{ useState } from 'react';\nimport '.\/App.css';\nimport Count from '.\/components\/Count.js'\n\nfunction App() {\n\n  const [display, setDisplay] = useState(true)\n\n  return (\n    <div className=\"App\">\n      <h1>Learn useEffect<\/h1>\n      <button onClick={()=>setDisplay(!display)}>Toggle<\/button>\n      {display && <Count\/>}\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092display\u304ctrue, false\u3067\u8868\u793a\u30fb\u975e\u8868\u793a\u306b\u5207\u308a\u66ff\u3048\u308b\u305f\u3081\u306b\u4e0b\u8a18\u3092\u8ffd\u52a0\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\n{ display && <Count\/> }\n<\/code><\/pre>\n\n\n\n
\u30d6\u30e9\u30a6\u30b6\u3067\u78ba\u8a8d\u3059\u308b\u3068Toggle\u30dc\u30bf\u30f3\u304c\u8868\u793a\u3055\u308c\u30011\u79d2\u3054\u3068\u306bCount\u304c\u30a2\u30c3\u30d7\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\"Toggle\u30dc\u30bf\u30f3\u304c\u8868\u793a\u3055\u308c\u305f\u72b6\u614b\"
Toggle\u30dc\u30bf\u30f3\u304c\u8868\u793a\u3055\u308c\u305f\u72b6\u614b<\/figcaption><\/figure>\n\n\n\n
Toggle\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3068Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u975e\u8868\u793a\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
\"Toggle\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u5f8c\"
Toggle\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u5f8c<\/figcaption><\/figure>\n\n\n\n
\u30b3\u30f3\u30bd\u30fc\u30eb\u3092\u78ba\u8a8d\u3059\u308b\u3068\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u975e\u8868\u793a\u306b\u306a\u308a\u3001\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3055\u308c\u305f\u306e\u3067\u3001\u201d\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3057\u307e\u3057\u305f\u201d\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u304c\u3001Warning\u304c\u767a\u751f\u3057\u3001memory leak\u306b\u3064\u3044\u3066\u306e\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8a18\u8ff0\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u307e\u305f\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u6d88\u3048\u305f\u306e\u306b\u3082\u95a2\u308f\u3089\u305a\u30ab\u30a6\u30f3\u30c8\u30a2\u30c3\u30d7\u306e\u30e1\u30c3\u30bb\u30fc\u30b8(\u30ab\u30a6\u30f3\u30c8\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3057\u305f)\u306f\u7d99\u7d9a\u3057\u3066\u8868\u793a\u3055\u308c\u3066\u3044\u308b\u3053\u3068\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n
\"\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306b\u30a8\u30e9\u30fc\"
\u30b3\u30f3\u30bd\u30fc\u30eb\u30ed\u30b0\u306b\u30a8\u30e9\u30fc<\/figcaption><\/figure>\n\n\n\n
\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\u51e6\u7406\u306e\u8ffd\u52a0<\/h3>\n\n\n\n
\u3053\u306e\u554f\u984c\u3092\u89e3\u6c7a\u3059\u308b\u305f\u3081\u306b\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u51e6\u7406\u306e\u4e2d\u3067setInterval\u3092\u30af\u30ea\u30fc\u30f3\u30a2\u30c3\u30d7\u3059\u308b\u51e6\u7406\u3092\u8ffd\u52a0\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\nuseEffect(() => {\n    console.log('useEffect\u304c\u5b9f\u884c\u3055\u308c\u307e\u3057\u305f')\n\n    const interval = setInterval(() => {\n        setCount(count => count + 1)\n        console.log('\u30ab\u30a6\u30f3\u30c8\u304c1\u30a2\u30c3\u30d7\u3057\u307e\u3057\u305f')\n        }, 1000)\n\n    return () => {\n        clearInterval(interval)\n        console.log('\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u304c\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3057\u307e\u3057\u305f')\n    }\n},[])\n<\/code><\/pre>\n\n\n\n
setInterval\u3092interval\u5909\u6570\u306b\u8a2d\u5b9a\u3057\u3001return\u306e\u4e2d\u3067clearInterval\u3092\u5b9f\u884c\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\u518d\u5ea6\u30d6\u30e9\u30a6\u30b6\u3067Toggle\u30dc\u30bf\u30f3\u3092\u62bc\u3057\u3066Count\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u3092\u975e\u8868\u793a\u306b\u3059\u308b\u3068\u5148\u7a0b\u306ewarning\u30e1\u30c3\u30bb\u30fc\u30b8\u3082\u8868\u793a\u3055\u308c\u305a\u3001\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3057\u305f\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\"\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u30e1\u30c3\u30bb\u30fc\u30b8\"
\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u30e1\u30c3\u30bb\u30fc\u30b8<\/figcaption><\/figure>\n\n\n\n
\u3053\u306e\u3088\u3046\u306buseEffect\u3067\u306f\u30de\u30a6\u30f3\u30c8\u6642\u306b\u5b9f\u884c\u3057\u305f\u51e6\u7406\u3092\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u6642\u306b\u89e3\u9664\u3059\u308b\u51e6\u7406\u304c\u5fc5\u8981\u3068\u306a\u308b\u3053\u3068\u3092\u899a\u3048\u3066\u3044\u3066\u304f\u3060\u3055\u3044\u3002setInterval\u3060\u3051\u3067\u306f\u306a\u304f\u30a4\u30d9\u30f3\u30c8\u306e\u8a2d\u5b9a\u306a\u3069\u3082\u89e3\u9664\u3092\u5fd8\u308c\u306a\u3044\u3068\u30a2\u30f3\u30de\u30a6\u30f3\u30c8\u3057\u3066\u3082\u30a4\u30d9\u30f3\u30c8\u304c\u524a\u9664\u3055\u308c\u305a\u6b8b\u3063\u305f\u307e\u307e\u306b\u306a\u3063\u3066\u3057\u307e\u3044\u307e\u3059\u3002(addEventListener\u3068\u5b9f\u884c\u3057\u305f\u3089removeEventListener\u3092\u8a2d\u5b9a\uff09<\/p>\n\n\n\n
useLayoutEffect<\/h2>\n\n\n\n
React\u306eHook\u306b\u306fuseEffect\u3068\u8868\u793a\u306b\u4f3c\u305f\u540d\u524d\u3068useLayoutEffect\u3068\u3044\u3046Hook\u304c\u3042\u308a\u307e\u3059\u3002useEffect\u3068useLayoutEffect\u306f\u4f7f\u3044\u65b9\u3001\u8a18\u8ff0\u65b9\u6cd5\u306b\u3064\u3044\u3066\u306f\u4f3c\u3066\u3044\u308b\u306e\u3067\u3059\u304c\u5927\u304d\u306a\u9055\u3044\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
useEffect\u306f\u4e00\u5ea6\u753b\u9762\u304c\u63cf\u5199\u3055\u308c\u305f\u5f8c\u306buseEffect\u306e\u4e2d\u306e\u51e6\u7406\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002useLayoutEffect\u306f\u753b\u9762\u304c\u63cf\u5199\u3055\u308c\u308b\u306buseLayoutEffect\u306e\u4e2d\u306e\u51e6\u7406\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\u30b3\u30fc\u30c9\u3092\u5229\u7528\u3057\u3066\u9055\u3044\u3092\u78ba\u8a8d\u3057\u3066\u307f\u307e\u3057\u3087\u3046\u3002\u307e\u305a\u4e0b\u8a18\u306e\u3088\u3046\u306buseEffect\u3092\u5229\u7528\u3057\u3066\u30b3\u30fc\u30c9\u3092\u8a18\u8ff0\u3057\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport { useState, useEffect } from 'react';\n\nfunction App() {\n  const [count, setCount] = useState(99999);\n\n  useEffect(() => {\n    setCount(0);\n  }, []);\n  return <div>{count}<\/div>;\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u30d6\u30e9\u30a6\u30b6\u3067\u52d5\u4f5c\u78ba\u8a8d\u3059\u308b\u3068\u4e00\u77ac99999\u304c\u8868\u793a\u3055\u308c\u3066\u5f8c\u306b0\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002\u3053\u308c\u306f\u5148\u7a0b\u8aac\u660e\u3057\u305f\u901a\u308auseEffect\u3067\u306f\u4e00\u5ea6\u753b\u9762\u304c\u63cf\u5199\u3055\u308c\u305f\u5f8c\u306buseEffect\u306e\u4e2d\u306e\u30b3\u30fc\u30c9\u304c\u5b9f\u884c\u3055\u308c\u308b\u305f\u3081\u3053\u306e\u3088\u3046\u306a\u52d5\u4f5c\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport { useState, useLayoutEffect } from 'react';\n\nfunction App() {\n  const [count, setCount] = useState(99999);\n\n  useLayoutEffect(() => {\n    setCount(0);\n  }, []);\n  return <div>{count}<\/div>;\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
useLayoutEffect\u306b\u66f8\u304d\u5909\u3048\u307e\u3059\u3002useLayoutEffct\u3067\u306f\u753b\u9762\u304c\u63cf\u5199\u3055\u308c\u308b\u524d\u306b\u5b9f\u884c\u3055\u308c\u308b\u305f\u3081\u521d\u671f\u5024\u3067\u3042\u308b99999\u304c\u753b\u9762\u306b\u8868\u793a\u3055\u308c\u308b\u3053\u3068\u306f\u306a\u304f0\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\u6b21\u306e\u4f8b\u3067\u306fdiv\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3092\u884c\u3044\u80cc\u666f\u8272\u3092\u5909\u66f4\u3059\u308b\u3053\u3068\u3067\u9055\u3044\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002useRef\u3092\u5229\u7528\u3057\u3066div\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3092\u884c\u3044\u80cc\u666f\u8272\u3092\u8d64\u306b\u5909\u66f4\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\nimport { useState, useEffect, useRef } from 'react';\n\nfunction App() {\n  const [count, setCount] = useState(99999);\n  const divElement = useRef();\n\n  useEffect(() => {\n    setCount(0);\n    const element = divElement.current;\n    element.style.backgroundColor = 'red';\n  }, []);\n  return (\n    <div ref={divElement} style={{ backgroundColor: 'blue' }}>\n      {count}\n    <\/div>\n  );\n}\n\nexport default App;\n<\/code><\/pre>\n\n\n\n
\u30c7\u30d5\u30a9\u30eb\u30c8\u3067\u306fstyle\u5c5e\u6027\u3067blue\u306b\u8a2d\u5b9a\u3057\u3066\u3044\u308bdiv\u8981\u7d20\u306e\u80cc\u666f\u8272\u306f\u9752\u306b\u306a\u308a\u307e\u3059\u3002useEffect\u3067\u306f\u4e00\u5ea6\u63cf\u5199\u304c\u884c\u308f\u308c\u306e\u3067\u4e00\u8272\u80cc\u666f\u8272\u304c\u9752\u306b\u306a\u308a\u307e\u3059\u304cuseEffect\u306b\u3088\u3063\u3066\u8d64\u3078\u3068\u5909\u66f4\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
useRef<\/h2>\n\n\n\n
useRef\u306f\u8981\u7d20\u3078\u306e\u53c2\u7167\u3092\u884c\u3046\u3053\u3068\u3068\u5024\u3092\u4fdd\u6301\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u308b\u3002
\u5024\u306e\u4fdd\u6301\u306b\u3064\u3044\u3066\u306fuseState\u3067\u3082\u540c\u69d8\u306e\u3053\u3068\u304c\u53ef\u80fd\u3067\u3059\u304c\u3001useState \u3068\u306f\u7570\u306a\u308a\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306e\u518d\u63cf\u5199\u304c\u884c\u308f\u308c\u306a\u3044\u3002
<\/p>\n\n\n\n
import { useState } from 'react';\n\nfunction App() {\n  const [name, setName] = useState('');\n  const handleOnChange = (e) => setName(e.target.value);\n\n  return (\n    <div style={{ margin: '2em' }}>\n      <input type="text" value={name} onChange={handleOnChange} \/>\n      <p>\u540d\u524d\uff1a{name}<\/p>\n    <\/div>\n  );\n}\n\nexport default App;<\/code><\/pre><\/div>\n\n\n\n
\u8868\u793a\u3055\u308c\u3066\u3044\u308b input \u8981\u7d20\u306b\u306f\u30d5\u30a9\u30fc\u30ab\u30b9\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u30d5\u30a9\u30fc\u30ab\u30b9\u3092\u5f53\u3066\u308b\u305f\u3081\u306b\u306f\u81ea\u5206\u3067\u30ab\u30fc\u30bd\u30eb\u3092 input \u8981\u7d20\u306b\u6301\u3063\u3066\u3044\u304f\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002input \u8981\u7d20\u306b\u30d5\u30a9\u30fc\u30ab\u30b9\u304c\u5f53\u305f\u308b\u3068\u6587\u5b57\u5217\u3092\u5165\u529b\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u3001\u5165\u529b\u3057\u305f\u6587\u5b57\u306f input \u8981\u7d20\u306e\u4e0b\u306b\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
useRef \u306e\u5f15\u6570\u306b\u306f\u521d\u671f\u5024\u3092\u8a2d\u5b9a\u3057\u307e\u3059<\/p>\n\n\n\n
<\/code><\/pre><\/div>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3068current \u30d7\u30ed\u30d1\u30c6\u30a3<\/strong>\u306b input \u304c\u5165\u3063\u3066\u3044\u308b\u3053\u3068\u304c\u30b3\u30f3\u30bd\u30fc\u30eb\u306b\u304a\u3044\u3066\u5206\u304b\u308a\u307e\u3059\u3002<\/p>\n\n\n\n
import '.\/App.css';\nimport { useState, useRef } from 'react';\n\nfunction App() {\n  const [name, setName] = useState('');\n  const handleOnChange = (e) => setName(e.target.value)\n  const inputEl = useRef(null);\n  const handleOnClick = () => inputEl.current.focus();\n\n  return (\n    <div className="App">\n      <input ref={inputEl} type='text' value={name} onChange={handleOnChange} \/>\n      <p>\u540d\u524d\uff1a{name}<\/p>\n      <button onClick={handleOnClick}>input\u306b\u30d5\u30a9\u30fc\u30ab\u30b9<\/button>\n    <\/div>\n  );\n}\n\nexport default App;<\/code><\/pre><\/div>\n\n\n\n
useRef \u3092\u5229\u7528\u3059\u308b\u3053\u3068\u3067 ref \u5c5e\u6027\u3067\u8a2d\u5b9a\u3057\u305f\u8981\u7d20\u3078\u306e\u53c2\u7167\u3092\u53d6\u5f97\u3067\u304d\u308b\u3053\u3068\u304c\u308f\u304b\u308a\u307e\u3059\u3002
\u53c2\u7167\u3092\u5229\u7528\u3057\u3066 DOM \u306b\u30a2\u30af\u30bb\u30b9\u3067\u304d\u308b\u3068\u3044\u3046\u3053\u3068\u306f\u30a2\u30af\u30bb\u30b9\u3057\u305f\u8981\u7d20\u306e\u60c5\u5831\u3092 getBoundingClientRect \u30e1\u30bd\u30c3\u30c9\u3092\u5229\u7528\u3057\u3066\u53d6\u5f97\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
React\u306eHook\u306e\u4e2d\u3067\u3082useState\u306e\u6b21\u306b\u4f7f\u7528\u983b\u5ea6\u3082\u9ad8\u304f\u91cd\u8981\u306auseEffect\u306e\u4f7f\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8aac\u660e\u3092\u884c\u306a\u3063\u3066\u3044\u307e\u3059\u3002 \u30b7\u30f3\u30d7\u30eb\u306a\u30b3\u30fc\u30c9\u3092\u5229\u7528\u3057\u3066\u3044\u308b\u306e\u3067\u672c\u6587\u66f8\u3092\u8aad\u307f\u7d42\u3048\u308b\u3068useEffect\u306e\u57fa\u672c\u7684\u306a\u4f7f\u7528\u65b9\u6cd5<\/p>\n","protected":false},"author":1,"featured_media":2741,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jin_ogp_image_url":"","_jin_last_featured_id":0,"footnotes":""},"categories":[21],"tags":[],"class_list":["post-2099","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-react"],"_links":{"self":[{"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/posts\/2099","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/agile-software.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2099"}],"version-history":[{"count":6,"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/posts\/2099\/revisions"}],"predecessor-version":[{"id":2738,"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/posts\/2099\/revisions\/2738"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/agile-software.net\/index.php?rest_route=\/wp\/v2\/media\/2741"}],"wp:attachment":[{"href":"https:\/\/agile-software.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2099"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/agile-software.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2099"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/agile-software.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2099"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}