{"id":1152,"date":"2024-05-16T21:28:39","date_gmt":"2024-05-16T12:28:39","guid":{"rendered":"https:\/\/shinke1987.net\/?p=1152"},"modified":"2024-05-16T21:35:23","modified_gmt":"2024-05-16T12:35:23","slug":"react%ef%bc%9ausememo%e3%81%ae%e5%8b%95%e4%bd%9c%e7%a2%ba%e8%aa%8d","status":"publish","type":"post","link":"https:\/\/shinke1987.net\/?p=1152","title":{"rendered":"React\uff1auseMemo\u306e\u52d5\u4f5c\u78ba\u8a8d"},"content":{"rendered":"\n<h2 id=\"toc0\" class=\"wp-block-heading\">\u74b0\u5883<\/h2>\n\n\n\n<p>React\uff1av18.3.1<\/p>\n\n\n\n<h2 id=\"toc1\" class=\"wp-block-heading\">Tips<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u95a2\u6570\u306e\u5b9f\u884c\u7d50\u679c\u3092\u30ad\u30e3\u30c3\u30b7\u30e5\u3057\u3066\u304a\u304d\u3001<br>\u4f9d\u5b58\u5024\u304c\u5909\u5316\u3057\u306a\u3044\u9650\u308a\u30ad\u30e3\u30c3\u30b7\u30e5\u3092\u8fd4\u3059\u3001\u3068\u3044\u3063\u305f\u52d5\u4f5c\u3092\u5b9a\u7fa9\u3059\u308b\u305f\u3081\u306e\u30d5\u30c3\u30af\u3002<\/li>\n\n\n\n<li>memo\u95a2\u6570\u3084useCallback\u30d5\u30c3\u30af\u306f\u5fc5\u8981\u6027\u3092\u611f\u3058\u3066\u304b\u3089\u52d5\u4f5c\u78ba\u8a8d\u3059\u308b\u3002<\/li>\n<\/ul>\n\n\n\n<h2 id=\"toc2\" class=\"wp-block-heading\">\u6bd4\u8f03<\/h2>\n\n\n\n<h3 id=\"toc3\" class=\"wp-block-heading\">useMemo\u3092\u4f7f\u308f\u306a\u3044\u5834\u5408<\/h3>\n\n\n\n<h4 id=\"toc4\" class=\"wp-block-heading\">TestUseMemo.tsx\u306e\u5185\u5bb9<\/h4>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: jscript; title: ; notranslate\" title=\"\">\nfunction TestUseMemo() {\n  const funcMemo = (() =&gt; {\n    let temp = 0;\n    for (let i = 0; i &lt; 4000000000; i++) {\n      temp += i;\n    }\n    return temp;\n  });\n\n  function handleClickBtn() {\n    console.log(&#039;start date = &#039;, Date());\n    console.log(&#039;funcMemo = &#039;, funcMemo());\n    console.log(&#039;end date = &#039;, Date());\n  }\n\n  return (\n    &lt;&gt;\n      TestUseMemo.tsx\n      &lt;br \/&gt;\n      &lt;button type=&quot;button&quot; onClick={handleClickBtn}&gt;\n        \u30dc\u30bf\u30f3\n      &lt;\/button&gt;\n    &lt;\/&gt;\n  );\n}\n\nexport default TestUseMemo;\n<\/pre><\/div>\n\n\n<h4 id=\"toc5\" class=\"wp-block-heading\">\u7d50\u679c\uff08\u30b3\u30f3\u30bd\u30fc\u30eb\u306e\u8868\u793a\u5185\u5bb9\uff09<\/h4>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nstart date =  Thu May 16 2024 17:48:07 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nfuncMemo =  7999999996067115000\nend date =  Thu May 16 2024 17:48:10 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nstart date =  Thu May 16 2024 17:48:12 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nfuncMemo =  7999999996067115000\nend date =  Thu May 16 2024 17:48:16 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\n<\/pre><\/div>\n\n\n<p>1\u56de\u76ee\u30822\u56de\u76ee\u3082\u7d043\u301c4\u79d2\u304b\u304b\u3063\u3066\u3044\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002<\/p>\n\n\n\n<h3 id=\"toc6\" class=\"wp-block-heading\">useMemo\u3092\u4f7f\u3046\u5834\u5408<\/h3>\n\n\n\n<h4 id=\"toc7\" class=\"wp-block-heading\">TestUseMemo.tsx\u306e\u5185\u5bb9<\/h4>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: jscript; title: ; notranslate\" title=\"\">\nimport { useMemo } from &#039;react&#039;;\n\nfunction TestUseMemo() {\n  const funcMemo = useMemo(() =&gt; {\n    let temp = 0;\n    for (let i = 0; i &lt; 4000000000; i++) {\n      temp += i;\n    }\n    return temp;\n  }, &#x5B;]);\n\n  function handleClickBtn() {\n    console.log(&#039;start date = &#039;, Date());\n    console.log(&#039;funcMemo = &#039;, funcMemo);\n    console.log(&#039;end date = &#039;, Date());\n  }\n\n  return (\n    &lt;&gt;\n      TestUseMemo.tsx\n      &lt;br \/&gt;\n      &lt;button type=&quot;button&quot; onClick={handleClickBtn}&gt;\n        \u30dc\u30bf\u30f3\n      &lt;\/button&gt;\n    &lt;\/&gt;\n  );\n}\n\nexport default TestUseMemo;\n<\/pre><\/div>\n\n\n<h4 id=\"toc8\" class=\"wp-block-heading\">\u7d50\u679c\uff08\u30b3\u30f3\u30bd\u30fc\u30eb\u306e\u8868\u793a\u5185\u5bb9\uff09<\/h4>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\nstart date =  Thu May 16 2024 17:52:09 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nfuncMemo =  7999999996067115000\nend date =  Thu May 16 2024 17:52:09 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nstart date =  Thu May 16 2024 17:52:16 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\nfuncMemo =  7999999996067115000\nend date =  Thu May 16 2024 17:52:16 GMT+0900 (\u65e5\u672c\u6a19\u6e96\u6642)\n<\/pre><\/div>\n\n\n<p>\u30ec\u30f3\u30c0\u30ea\u30f3\u30b0\u6642\u306b\u95a2\u6570\u306e\u5b9f\u884c\u7d50\u679c\u304c\u30ad\u30e3\u30c3\u30b7\u30e5\u3055\u308c\u3066\u3044\u308b\u306e\u3067\u3001\u5373\u8fd4\u3055\u308c\u308b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u74b0\u5883 React\uff1av18.3.1 Tips \u6bd4\u8f03 useMemo\u3092\u4f7f\u308f\u306a\u3044\u5834\u5408 TestUseMemo.tsx\u306e\u5185\u5bb9 \u7d50\u679c\uff08\u30b3\u30f3\u30bd\u30fc\u30eb\u306e\u8868\u793a\u5185\u5bb9\uff09 1\u56de\u76ee\u30822\u56de\u76ee\u3082\u7d043\u301c4\u79d2\u304b\u304b\u3063\u3066\u3044\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002 useMemo\u3092\u4f7f [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[104],"tags":[105],"class_list":["post-1152","post","type-post","status-publish","format-standard","hentry","category-react","tag-react"],"_links":{"self":[{"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/posts\/1152","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/shinke1987.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1152"}],"version-history":[{"count":2,"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/posts\/1152\/revisions"}],"predecessor-version":[{"id":1159,"href":"https:\/\/shinke1987.net\/index.php?rest_route=\/wp\/v2\/posts\/1152\/revisions\/1159"}],"wp:attachment":[{"href":"https:\/\/shinke1987.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1152"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/shinke1987.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1152"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/shinke1987.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}