投稿時間:2021-06-30 17:46:07 RSSフィード2021-06-30 17:00 分まとめ(68件)

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IT	＠IT Smart & Socialフォーラム 最新記事一覧	1枚の写真から動画を作成するディープラーニング手法を開発、ワシントン大	https://www.atmarkit.co.jp/ait/articles/2106/30/news121.html	開発	2021-06-30 16:30:00
TECH	Engadget Japanese	iPhone 13（仮)のダミーモデル流出、ノッチ小型化やカメラ配置が変更	https://japanese.engadget.com/iphone13-dummymodel-smaller-notch-074012925.html	iphone	2021-06-30 07:40:12
TECH	Engadget Japanese	50GBで月額2728円、ビッグローブが格安SIMの新ブランド「donedone」発表	https://japanese.engadget.com/biglobe-mobile-service-donedone-073554182.html	biglobe	2021-06-30 07:35:54
フリーソフト	新着ソフトレビュー - Vector	パソコンならではの高い検索性で、全上場企業の豊富なデータをフル活用できる「会社四季報CD-ROM ダウンロード版」	https://www.vector.co.jp/magazine/softnews/151219/n1512191.html?ref=rss	cdrom	2021-06-30 17:00:00
IT	＠IT 全フォーラム 最新記事一覧	1枚の写真から動画を作成するディープラーニング手法を開発、ワシントン大	https://www.atmarkit.co.jp/ait/articles/2106/30/news121.html	開発	2021-06-30 16:30:00
IT	ITmedia 総合記事一覧	[ITmedia ビジネスオンライン] アダストリア、21年3～5月期は2億円の黒字転換　店舗の営業環境が改善	https://www.itmedia.co.jp/business/articles/2106/30/news145.html	itmedia	2021-06-30 16:45:00
IT	ITmedia 総合記事一覧	[ITmedia News] オリコン、取引先情報1万7000件漏えいの可能性　社員のメールアカウントに不正ログイン	https://www.itmedia.co.jp/news/articles/2106/30/news146.html	itmedia	2021-06-30 16:36:00
IT	ITmedia 総合記事一覧	[ITmedia ビジネスオンライン] 昭文社HD、夏季賞与ゼロに　賞与引当金の取り崩しで、営業損失を軽減へ	https://www.itmedia.co.jp/business/articles/2106/30/news144.html	itmedia	2021-06-30 16:23:00
IT	ITmedia 総合記事一覧	[ITmedia ビジネスオンライン] 鳥貴族のチキンバーガー専門店「TORIKI BURGER」　8月オープン予定	https://www.itmedia.co.jp/business/articles/2106/30/news138.html	itmedia	2021-06-30 16:20:00
IT	ITmedia 総合記事一覧	[ITmedia PC USER] デル、4K/HDR対応のハイスペックWebカメラ	https://www.itmedia.co.jp/pcuser/articles/2106/30/news143.html	itmediapcuser	2021-06-30 16:20:00
IT	ITmedia 総合記事一覧	[ITmedia News] 新モバイルブランド「donedone」（ドネドネ）　50GB・2480円＋社会貢献	https://www.itmedia.co.jp/news/articles/2106/30/news139.html	社会貢献	2021-06-30 16:15:00
IT	ITmedia 総合記事一覧	[ITmedia News] TENGAロケット、無観客の打ち上げ決定に「さすが感染対策は万全」の声	https://www.itmedia.co.jp/news/articles/2106/30/news140.html	itmedianewstenga	2021-06-30 16:11:00
IT	MOONGIFT	Helix - Rust製の軽量なテキストエディタ	http://feedproxy.google.com/~r/moongift/~3/sC-yVw1b0hA/	helix	2021-06-30 17:00:00
TECH	Techable（テッカブル）	iOS・iPadOS版も登場！ ヤマハのリモート合奏サービス「SYNCROOM」	https://techable.jp/archives/157384	android	2021-06-30 07:00:09
AWS	lambdaタグが付けられた新着投稿 - Qiita	LambdaとS3の連携	https://qiita.com/pankata79/items/a8e7110fe61d98531b46	アクセス権限の方をみると、CloudWacthlogs以外にもリソースベースのポリシーの欄に新しくSにLambdaを呼び出すアクションが許可されてると思います。	2021-06-30 16:09:57
js	JavaScriptタグが付けられた新着投稿 - Qiita	Paizaレベルアップ問題集 - 私の回答コード(JavaScript編)	https://qiita.com/chabudai/items/fcb4a1767f109932dd36	Paiza様の実行環境上では全てのテストにクリアしたコードですが、バグや正確性に問題が無い保証はありません。	2021-06-30 16:46:02
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	FASTX-Toolkitを使うために，makeコマンドで発生するエラーの解決方法	https://teratail.com/questions/346952?rss=all		2021-06-30 16:55:08
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	flexで配置した画像を縦並びにすると画像サイズが統一できない	https://teratail.com/questions/346951?rss=all	flexで配置した画像を縦並びにすると画像サイズが統一できないDW上だと思い通りにpxで画面サイズいっぱいに表示されるのですが、サーバーにアップロードすると画像サイズがバラバラになってしまい困っています。	2021-06-30 16:48:26
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	railsとvueでバリデーションで弾かれた際に422 (Unprocessable Entity)が出てしまう。	https://teratail.com/questions/346950?rss=all	railsとvueでバリデーションで弾かれた際にUnprocessableEntityが出てしまう。	2021-06-30 16:48:02
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	L2スイッチをスイッチングハブに変更	https://teratail.com/questions/346949?rss=all		2021-06-30 16:47:01
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Java 変数と配列について質問です。	https://teratail.com/questions/346948?rss=all	Java変数と配列について質問です。	2021-06-30 16:44:15
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	yaccの四則演算優先順位について	https://teratail.com/questions/346947?rss=all	yaccの四則演算優先順位について前提・実現したいことyaccで四則演算の定義を行ったのですが、掛け算が足し算、引き算よりも優先的に実行されるようにするにはどうすればいいでしょうか。	2021-06-30 16:42:22
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	No module named 'torch.nn'; 'torch' is not a package	https://teratail.com/questions/346946?rss=all	Nomodulenamedxtorchnnxxtorchxisnotapackagepytorchnbspnbspnbspgpunbspをインストールしたのですが、このエラー生じます。	2021-06-30 16:42:21
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	【Python】【GitHub】『Everybody Dance Now』というコードの実行	https://teratail.com/questions/346945?rss=all	【Python】【GitHub】『EverybodyDanceNow』というコードの実行こちらのgitのコードを実行させたいのですが、READMEの手順通りに進めると初めのコードで以下のようなエラーが出ます。	2021-06-30 16:40:55
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Ubuntu(WSL2)ホストからDockerの仮想的なブリッジ「docker0」が確認できない	https://teratail.com/questions/346944?rss=all	ある著名な方が紹介していたウェブ上の初学者向けのDocker入門サイト無料で学習をしています。	2021-06-30 16:39:28
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Pythonのcorr()のデータが正規分布について従っているかの条件について	https://teratail.com/questions/346943?rss=all	発生している問題・エラーメッセージPythonで、corrを使うと、相関係数が出ますが、これがピアソンの相関係数を元に作られていることがわかりました。	2021-06-30 16:31:49
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	python 日付加工	https://teratail.com/questions/346942?rss=all	python日付加工dataaposnowdatenbspnbspdataaposstartdateaposnbspTESTrelativedeltadatanowdatedatastartdateTESTの実行結果がrelativedeltamonthsnbspdaysで、dataperiodintTESTyearsTESTmonthsdataperiodの実行結果がです。	2021-06-30 16:31:25
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Javaの再帰関数のトレースプログラム	https://teratail.com/questions/346941?rss=all		2021-06-30 16:25:29
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	デプロイ時にTailwind css が機能しない	https://teratail.com/questions/346940?rss=all	デプロイ時にTailwindcssが機能しないcloudfrontにデプロイ後tailwindnbspcssが機能しません。	2021-06-30 16:24:18
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	/var/lib/docker/overlay2が肥大化するのを恒久対応したい	https://teratail.com/questions/346939?rss=all	varlibdockeroverlayが肥大化するのを恒久対応したい経緯使用しているdockerのディスク容量がいっぱいになってしまっていて、原因を調べるとvarlibdockeroverlayがほとんどの割合を占めていた。	2021-06-30 16:18:59
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	centOS上にdocker compose で作成したコンテナにphp環境を作成し、apiを作成しアクセスしたい	https://teratail.com/questions/346938?rss=all	centOS上にdockercomposeで作成したコンテナにphp環境を作成し、apiを作成しアクセスしたいcentOS上にdockerをいれてcentosのイメージを元にphpnbspLaravel環境を作成しました。	2021-06-30 16:14:22
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	2変数関数を一文字固定して最適化したい	https://teratail.com/questions/346937?rss=all	変数関数を一文字固定して最適化したい前提・実現したいこと変数関数において変数の片方を固定し、変数関数にして最適化する処理を考えています。	2021-06-30 16:11:34
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Tkinterで、ボタンを押すとラベルが変更され表示される→その３秒後にラベルがさらに変更され表示されるというプログラムを作りたいです。	https://teratail.com/questions/346936?rss=all	Tkinterで、ボタンを押すとラベルが変更され表示される→その秒後にラベルがさらに変更され表示されるというプログラムを作りたいです。	2021-06-30 16:11:13
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	GASからgoogleカレンダーに入力できない	https://teratail.com/questions/346935?rss=all	GASからgoogleカレンダーに入力できない前提・実現したいことGoogleAppsScriptGASにてgoogleフォームからgoogleカレンダー自動記入アプリのコードを書いている途中、エラーが起こり、解決できませんどこでエラーが起きているのかはわかりますが途中のログに出てくるNull、なぜ出るのかがわからずすべてにnullがでるならコードが間違っている可能性があるので一からやり直しますが、一つだけnullが出てきます。	2021-06-30 16:10:05
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Hololens2にてPhotoCaptureで撮影した写真をTexture2Dに変換してQurdなどに表示させたい	https://teratail.com/questions/346934?rss=all	HololensにてPhotoCaptureで撮影した写真をTextureDに変換してQurdなどに表示させたい前提・実現したいことMicroSoftの公式ドキュメントにあるPhotoCaptureを利用して、撮影した写真をTextureDに変換してから、Qurdなどに表示したい。	2021-06-30 16:07:47
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	EEFC0の使い方について	https://teratail.com/questions/346933?rss=all	EEFCの使い方についてArduinonbspDueのMicrocontroller「ATSAMXE」のセキュリティ・ビットを有効にすればフラッシュメモリの読み書きを禁止にできるそうです。	2021-06-30 16:06:34
Ruby	Rubyタグが付けられた新着投稿 - Qiita	【Ruby】小数の計算での丸め誤差について	https://qiita.com/hmae12/items/0827ef4d997d3db29bd2	【Ruby】小数の計算での丸め誤差について丸め誤差Rubyでは以下のように小数の計算で期待しない結果になることがある。	2021-06-30 16:36:27
AWS	AWSタグが付けられた新着投稿 - Qiita	LambdaとS3の連携	https://qiita.com/pankata79/items/a8e7110fe61d98531b46	アクセス権限の方をみると、CloudWacthlogs以外にもリソースベースのポリシーの欄に新しくSにLambdaを呼び出すアクションが許可されてると思います。	2021-06-30 16:09:57
GCP	gcpタグが付けられた新着投稿 - Qiita	Terraformの流れ	https://qiita.com/popo62520908/items/0dd705dbe5528786d0a5	Terraformの流れ今回Terraformを使う機会があり、まだ全然理解できていないが、流れだけをメモ。	2021-06-30 16:03:34
Ruby	Railsタグが付けられた新着投稿 - Qiita	herokuへデプロイする際のエラー	https://qiita.com/taiti101112/items/98f5a6795aab28c5c1d3	herokudestroyappglacialmeadowアプリ名このコマンドで指定したアプリを削除することができます。	2021-06-30 16:50:01
技術ブログ	Developers.IO	AWS CLI の S3 コマンドで表示される「Completed」というログを記録させない方法を教えてください	https://dev.classmethod.jp/articles/tsnote-s3-do-not-show-progress-in-the-log/	awscli	2021-06-30 07:44:33
技術ブログ	Developers.IO	ALBとEC2間をHTTPS通信させてApacheのアクセスログから接続元のクライアントIPを取得する	https://dev.classmethod.jp/articles/alb-ec2-https-accesslog/	etchttp	2021-06-30 07:17:52
海外TECH	DEV Community	Coding the code versus coding the code that codes	https://dev.to/infobipdev/coding-the-code-versus-coding-the-code-that-codes-4m44	Coding the code versus coding the code that codesAccording to Tiobe analysis there are close to programming languages today Their analysis is a bit complex though It rules out markup languages and frameworks from the equation it also expects programming languages to have a certain number of Google search hits in order to include them etc About ⅔of programming languages listed there I ve never even heard of And mind you I ve coded anything in just a bit under two dozen of them At the same time there are about code generators out there Some of them support a significant number of those programming languages Within the community however there are polarized views on when to go with generating as opposed to coding the whole thing manually A dilemmaDo you even have to pick one over the other I m a bit biased here I do both Some of it I code and some of it I find easier to generate and even more easy to maintain Do I think one is better than the other YES And also NO It s basically up to the person to decide how they want to approach a certain challenge I ll get back to this later If you stick until the end of this blog post you ll see why we used and even built on top of the code generator Hence the pun in the title I know hilarious But for now back to the basics Here are some of the stronger arguments against using code generation tools It s an anti pattern Can reduce the performance Not as clean tidy and fancy written as manually written code can be Manually written code still does the same thing but better You cannot really generate business logic When you hear this you might wonder why even bother using something that might reduce performance Additionally potentially cause a worse experience if for example we re creating the library which wraps around HTTP API In my team in Infobip we do exactly that Challenge at handYou see here in Infobip my team is in charge of DevRel To simplify our main goal is to enhance the developer experience when using or better say integrating our platform If you are not familiar with Infobip our platform is about omnichannel engagement Our job is to help businesses of our clients and partners to communicate with their own clients while using any of the communication platforms we can provide A few months back we were set a challenge to upgrade API client libraries for the company s complete product stack for a programming language of our choice but which will continuously keep on adding additional features and programming languages We needed to make a decision on how to tackle this There were several options Creating libraries for dozens of products and dealing with different programming languages wasn t easy Upgrading existing ones at times can be even harder A lot of questions popped up as well as potential red flags How to scale it How not to end up in never ending library development in multiple different programming languages How not to create a horrible piece of software if we go with code generation Step up the game Some code generation tools are configurable and programmable You can do just about anything For example you are able to produce a complete set list of language specific details or which library should you use to generate a certain functionality But yes more often than not generated code does not look awesome Now why don t you write one piece of software and built on top of a certain code generator And then you can programmatically refine the generated code Let me introduce the OpenAPI Long story short OpenAPI Specification is an API description format for REST API Basically it s a file in which you can by following certain standards describe your entire API authentication and more The cool part is several code generation tools can read it understand it and translate it to a compilable working project in one or more available programming languages The tool we are using within my team is called OpenAPI Generator and we love it What we did was we wrote a service that consumes this tool and builds on top of it to enhance the generated code Yes we wrote it manually That service basically serves as a set of preprocessing and postprocessing steps around the configuration for code generation and extends the certain functionalities of the generator itself So what that means in our case is that among the rest we integrated a linter for each of the programming languages we are generating the code for Some linters simply give results that feel more natural and configuring the right one is of great importance We defined an additional set of rules to make it look more natural and less generic to someone to integrate that library into its own project When you think of it we literally extended a code generation tool by writing our own set of rules on some things Also we ve enriched the result of the code generation execution by both using the language specific options within the generator and furthermore by applying a linter to it Is it even worth it You might ask Well isn t this an overkill Or you might even go on and say Even if you saved time on learning the specifics of certain programming languages you still had to write the configuration for each and every one of those generations You had to implement the service which is building on top of it AND you had to test all that afterward and not simply just push it to the world to use it If you look at it that way then yes it s an overkill BUT Let s say you manually write all the code for a single product   a set of API methods by hand for all the programming languages And let s assume for the sake of the argument that it takes exactly the same amount of time to create the release ready product in both cases Would you still consider using code generators as an overkill approach If the answer was yes well I d have to disagree And I m going to break it down as to why I disagree In an ideal universe maybe but just maybe it would be safe to say that API will be built in such a way that no breaking changes will occur Take an even more utopian scenario where the product team created the API endpoints in such a way that they cover all the aspects of its usage all the use cases ever needed and that all the potential authentication processes are covert That does not happen like ever This means that for every single update you need to do you will have to write code for every programming language you used in the initial release Furthermore this means that you will keep having to do it over and over again And we only talked about one product written in several programming languages In reality we are not taking care of only one product We re talking about multiple products developed by different teams How would you handle that And up until this moment we talked about the code but there are so many more things that make a project complete So if you have a similar use case like my team I would be more inclined to say that an overkill would be manually coding over and over again all the things that need to be changed in every single programming language Instead in most cases all we need to tweak after an initial release is that OpenAPI Specification And it will use the same building blocks we prepared up until that point and do the heavy work for us Understand your challenge I ve tried to emphasize this at the very beginning There isn t a deterministic answer as to which approach is better Well at least I don t see a deterministic answer As with most of the things in the world of software I find that it very much depends on what you are trying to achieve And on which problem are you trying to solve To be fair most of us do use code generation to some extent every single day If you re programming in a language like Java using annotation libraries like Lombok per definition ends up with having parts of your code generated in the compile time But whichever side you are leaning on do what feels the best for you When facing certain challenges take your time Try to get a bigger picture rather than trying to solve the issue instantly It just might save you a ton of time later on	2021-06-30 07:13:04
海外TECH	DEV Community	My Top React Interview Questions	https://dev.to/mokkapps/my-top-react-interview-questions-5hfb	My Top React Interview QuestionsThis article summarizes a list of React interview questions that I would ask candidates and that I get often asked in interviews Table of Contents What is React What are the advantages of React What are disadvantages of React What is JSX How to pass data between components What are the differences between functional and class components What is the Virtual DOM Is the Shadow DOM the same as the Virtual DOM What is “React Fiber How does state differ from props What are the differences between controlled and uncontrolled components What are the different lifecycle methods in React How can you improve your React app s performance What are keys in React What are Higher Order Components What are error boundaries Why Hooks were introduced What is the purpose of useEffect hook What are synthetic events in React What is the use of refs Conclusion What is React React is a “JavaScript library for building user interfaces which was developed by Facebook in It s the V in the MVC Model View Controller so it is rather an open source UI library than a framework What are the advantages of React Good performance due to VDOM see Easy to learn with basic JavaScript knowledge you can start building applications Frameworks like Angular require more knowledge about other technologies and patterns like RxJS TypeScript and Dependency Injection One way data flow this flow is also called “parent to child or “top to bottom and prevents errors and facilitates debugging Reusable components Re using React components in other parts of the code or even in different projects can be done with little or no changes Huge community The community supplies a ton of libraries that can be used to build React applications It is very popular among developers What are the disadvantages of React As React provides only the View part of the MVC model you mostly will rely on other technologies in your projects as well Therefore every React project might look quite different Some people think that JSX is too difficult to grasp and too complex Often poor documentation for React and its libraries What is JSX JSX JavaScript XML allows us to write HTML inside JavaScript The official docs describe it as “syntax extension to JavaScript React recommends using JSX but it is also possible to create applications without using JSX at all A simple JSX example const element lt h gt Hello world lt h gt How to pass data between components Use props to pass data from parent to child Use callbacks to pass data from child to parent Use any of the following methods to pass data among siblings Integrating the methods mentioned above Using Redux Utilizing React s Context API What are the differences between functional and class components Hooks were introduced in React In previous versions functional components were called stateless components and did not provide the same features as class components e g accessing state Hooks enable functional components to have the same features as class components There are no plans to remove class components from React So let s take a look at the differences Declaration amp Props Functional ComponentFunctional components are JavaScript functions and therefore can be declared using an arrow function or the function keyword Props are simply function arguments and can be directly used inside JSX const Card props gt return lt h gt Title props title lt h gt function Card props return lt h gt Title props title lt h gt Class componentClass components are declared using the ES class keyword Props need to be accessed using the this keyword class Card extends React Component constructor props super props render return lt h gt Title this props title lt h gt Handling state Functional componentsIn functional components we need to use the useState hook to be able to handle state const Counter props gt const counter setCounter useState const increment gt setCounter counter return lt div gt lt p gt Count counter lt p gt lt button onClick increment gt Increment Counter lt button gt lt div gt Class componentsIt s not possible to use React Hooks inside class components therefore state handling is done differently in a class component class Counter extends React Component constructor props super props this state counter this increment this increment bind this increment this setState prevState gt return counter prevState counter render return lt div gt lt p gt Count this state counter lt p gt lt button onClick this increment gt Increment Counter lt button gt lt div gt What is the Virtual DOM The Virtual DOM VDOM is a lightweight JavaScript object and it contains a copy of the real DOM Real DOMVirtual DOMSlow amp expensive DOM manipulationFast amp inexpensive DOM manipulationAllows direct updates from HTMLIt cannot be used to update HTML directlyWastes too much memoryLess memory consumption Is the Shadow DOM the same as the Virtual DOM No they are different The Shadow DOM is a browser technology designed primarily for scoping variables and CSS in web components The virtual DOM is a concept implemented by libraries in JavaScript on top of browser APIs What is “React Fiber Fiber is the new reconciliation engine in React Its headline feature is incremental rendering the ability to split rendering work into chunks and spread it out over multiple frames Read more How does state differ from props Both props and state are plain JavaScript objects Props short for “properties is an object of arbitrary inputs that are passed to a component by its parent component State are variables that are initialized and managed by the component and change over the lifetime of a specific instance of this component This article from Kent C Dodds provides a more detailed explanation What are the differences between controlled and uncontrolled components The value of an input element in a controlled React component is controlled by React The value of an input element in an uncontrolled React component is controlled by the DOM What are the different lifecycle methods in React React class components provide these lifecycle methods componentDidMount Runs after the component output has been rendered to the DOM componentDidUpdate Runs immediately after updating occurs componentWillUnmount Runs after the component is unmounted from the DOM and is used to clear up the memory space There exist some other rarely used and legacy lifecycle methods Hooks are used in functional components instead of the above mentioned lifecycle methods The Effect Hook useEffect adds for example the ability to perform side effects and provides the same functionality as componentDidMount componentDidUpdate and componentWillUnmount How can you improve your React app s performance Use React PureComponent which is a base class like React Component but it provides in some cases a performance boost if its render function renders the same result given the same props and state Use useMemo Hook to memoize functions that perform expensive calculations on every render It will only recompute the memoized value if one of the dependencies that are passed to the Hook has changed State colocation is a process that moves the state as close to where you need it Some React applications have a lot of unnecessary state in their parent component which makes the code harder to maintain and leads to a lot of unnecessary re renders This article provides a detailed explanation about state colocation Lazy load your components to reduce the load time of your application React Suspense can be used to lazy load components What are keys in React React needs keys to be able to identify which elements were changed added or removed Each item in an array needs to have a key that provides a stable identity It s not recommended to use indexes for keys if the order of items may change as it can have a negative impact on the performance and may cause state issues React will use indexes as keys if you do not assign an explicit key to list items Check out Robin Pokorny s article for an in depth explanation of the negative impacts of using an index as a key Here is another in depth explanation about why keys are necessary if you re interested in learning more What are Higher Order Components A higher order component HOC is a function that takes a component and returns a new component They are an advanced technique in React for reusing component logic and they are not part of the React API per se They are a pattern that emerges from React s compositional nature const EnhancedComponent higherOrderComponent WrappedComponent Whereas a component transforms props into UI a higher order component transforms a component into another component What are error boundaries React introduced a new concept of an “error boundary Error boundaries are React components that catch JavaScript errors anywhere in their child component tree log those errors and display a fallback UI instead of the component tree that crashed Error boundaries catch errors during rendering in lifecycle methods and in constructors of the whole tree below them Why Hooks were introduced Hooks solve a wide variety of seemingly unconnected problems in React that were encountered by Facebook over five years of writing and maintaining tens of thousands of components Hooks allow you to reuse stateful logic without changing your component hierarchy Hooks let you split one component into smaller functions based on what pieces are related such as setting up a subscription or fetching data Hooks let you use more of React s features without classes It removed the complexity of dealing with the this keyword inside class components Read more What is the purpose of useEffect hook The Effect hook lets us perform side effects in functional components It helps us to avoid redundant code in different lifecycle methods of a class component It helps to group related code What are synthetic events in React SyntheticEvent is a cross browser wrapper around the browser s native event It has the same API as the browser s native event including stopPropagation and preventDefault except the events work identically across all browsers What is the use of refs A Ref is a special attribute that can be attached to any component It can be an object created by React createRef a callback function or a string in legacy API To get direct access to a DOM element or component instance you can use ref attribute as a callback function The function receives the underlying DOM element or class instance depending on the type of element as its argument In most cases refs should be used sparingly ConclusionI hope this list of React interview questions will help you to get your next React position Leave me a comment if you know any other important React interview questions If you liked this article follow me on Twitter to get notified about new blog posts and more content from me If you are looking for more interview questions you should take a look at this list of top React interview questions amp answers	2021-06-30 07:01:51
医療系	医療介護 CBnews	陽性の上司と会議で隣席「マスク着用するも感染」-東京都が職場含めた「緊急・重点的強化策」公表	https://www.cbnews.jp/news/entry/20210630161522	危機管理	2021-06-30 16:25:00
金融	RSS FILE - 日本証券業協会	選択権付債券売買取引状況	https://www.jsda.or.jp/shiryoshitsu/toukei/sentaku/index.html	選択	2021-06-30 09:00:00
金融	RSS FILE - 日本証券業協会	短期社債等及び私募社債の取引状況等	https://www.jsda.or.jp/shiryoshitsu/toukei/kokunai/index.html	私募	2021-06-30 09:00:00
金融	RSS FILE - 日本証券業協会	インターネット取引に係る株式売買等データ(月次)	https://www.jsda.or.jp/shiryoshitsu/toukei/datakaiji.html	株式	2021-06-30 09:00:00
金融	RSS FILE - 日本証券業協会	教員向けセミナー	https://www.jsda.or.jp/gakusyu/edu/seminar/teacher_seminar.html	教員	2021-06-30 09:00:00
金融	ニッセイ基礎研究所	欧州復興基金の実相（３）－始まった債券発行、早期配分優先で進む審査－	https://www.nli-research.co.jp/topics_detail1/id=68137?site=nli	nbspカ国の復興計画の審査が終了復興基金の割を占める「復興・強靭化ファシリティーRRF」を通じた資金配分に関しても、月の第回の配分開始を目標とする、欧州委員会による加盟国のRRF利用計画以下、復興計画の審査が進んでいる。	2021-06-30 16:57:40
金融	ニッセイ基礎研究所	女性も軍隊に、なぜ韓国では「女性徴兵論」が浮上したのだろうか？	https://www.nli-research.co.jp/topics_detail1/id=68141?site=nli	そして、年に「軍加算点制度」が廃止されてから、兵役義務者に対する補償問題がジェンダーの論争に発展し、女性も兵役の義務を負うべきだという「女性徴兵論」に賛同する男性が増えている。	2021-06-30 16:24:51
金融	日本銀行：RSS	「日本銀行の役職員の報酬、給与等について」の公表について（令和2年度）	http://www.boj.or.jp/announcements/release_2021/rel210630c.htm	日本銀行	2021-06-30 17:00:00
金融	日本銀行：RSS	日本銀行政策委員会月報（令和3年5月号）	http://www.boj.or.jp/announcements/pb_geppo/pbgp2105.pdf	日本銀行政策委員会	2021-06-30 16:30:00
金融	ニュース - 保険市場TIMES	損保ジャパン、役員・従業員の疾病リスクを補償する『メディカル・マスター』を発売	https://www.hokende.com/news/blog/entry/2021/06/30/170000	損保ジャパン、役員・従業員の疾病リスクを補償する『メディカル・マスター』を発売中小企業向け事業活動総合保険の新プラン損保ジャパンは月日、中小企業向けの事業活動総合保険「ビジネスマスター・プラス」に、役員・従業員個人の疾病リスクを補償するプラン『メディカル・マスター』を月から販売すると発表した。	2021-06-30 17:00:00
海外ニュース	Japan Times latest articles	With Tokyo cases rising, Olympic organizers see ticket lottery complication	https://www.japantimes.co.jp/news/2021/06/30/national/torch-relay-public-roads/	With Tokyo cases rising Olympic organizers see ticket lottery complicationAn extension of current COVID measures would wreak havoc on organizers plans since it would require them to further whittle down the number of spectators	2021-06-30 16:36:56
海外ニュース	Japan Times latest articles	Shohei Ohtani stretches home run lead with 27th, 28th against Yankees	https://www.japantimes.co.jp/sports/2021/06/30/baseball/mlb/angels-yankees-ohtani-2hr/	games	2021-06-30 16:01:28
ニュース	BBC News - Home	Euro 2020: England focus turns to Ukraine for quarter-finals	https://www.bbc.co.uk/sport/football/57660584	finals	2021-06-30 07:33:14
ニュース	BBC News - Home	Canada weather: Dozens dead as heatwave shatters records	https://www.bbc.co.uk/news/world-us-canada-57654133	temperature	2021-06-30 07:15:29
LifeHuck	ライフハッカー［日本版］	【楽天セール】最大50%ポイント還元！ティファール電気圧力鍋が30%還元、レノア柔軟剤980ml×9袋が40％還元など	https://www.lifehacker.jp/2021/06/rakuten-sale-0630-1.html	楽天市場	2021-06-30 17:00:00
GCP	Google Cloud Platform Japan 公式ブログ	よりよい未来のために今、量子へのアクセスを拡大	https://cloud.google.com/blog/ja/products/compute/ionq-quantum-computer-available-through-google-cloud/	PeterChapman氏IonQは、量子システムへのアクセスを民主化することと同じくらい、量子コンピューティングで優れたハードウェアを構築することに重点を置いており、クラウドはハードウェアを広く利用可能にするという点でIonQに適しています。	2021-06-30 09:00:00
北海道	北海道新聞	妻子６人殺害で死刑判決　水戸地裁の裁判員裁判	https://www.hokkaido-np.co.jp/article/561629/	死刑判決	2021-06-30 16:03:37
北海道	北海道新聞	五輪バレー３６歳荒木が代表入り　黒後、籾井らは初めて	https://www.hokkaido-np.co.jp/article/561644/	代表入り	2021-06-30 16:08:00
北海道	北海道新聞	チセ跡、千島アイヌ…　根室の資料館が展示拡充	https://www.hokkaido-np.co.jp/article/561642/	千島アイヌ	2021-06-30 16:02:00
IT	週刊アスキー	大阪王将、東西異なる「道頓堀焼きそば」!!　とにかくボリューム満点だ	https://weekly.ascii.jp/elem/000/004/060/4060936/	大阪王将	2021-06-30 16:30:00
IT	週刊アスキー	ピクサー作品も登場！『ディズニー ミュージックパレード』がハーフアニバーサリーを開催	https://weekly.ascii.jp/elem/000/004/060/4060989/	音楽ゲーム	2021-06-30 16:15:00
IT	週刊アスキー	2年ぶりの開催！ 夜の動物園を楽しめる「よこはま夜の動物園2021」 金沢動物園など3園で	https://weekly.ascii.jp/elem/000/004/060/4060988/	野毛山動物園	2021-06-30 16:10:00
ニュース	THE BRIDGE	クリエイターのライブ配信SNS「00:00 Studio」でライブ制作依頼が可能に、ファンとの持続可能な関係づくりに一手	http://feedproxy.google.com/~r/SdJapan/~3/tCGOEpgFCQ0/0000-studio-makes-creators-more-sustainable	クリエイターのライブ配信SNS「Studio」でライブ制作依頼が可能に、ファンとの持続可能な関係づくりに一手ニュースサマリ創作活動をライブ配信できるソーシャルネットワーク「Studioフォーゼロスタジオ」を運営するアルは月日、クリエイターがライブ配信中にファンからの有償リクエストを受け付ける「リクエスト機能」の提供を開始した。	2021-06-30 07:16:47
GCP	Cloud Blog JA	よりよい未来のために今、量子へのアクセスを拡大	https://cloud.google.com/blog/ja/products/compute/ionq-quantum-computer-available-through-google-cloud/	PeterChapman氏IonQは、量子システムへのアクセスを民主化することと同じくらい、量子コンピューティングで優れたハードウェアを構築することに重点を置いており、クラウドはハードウェアを広く利用可能にするという点でIonQに適しています。	2021-06-30 09:00:00