投稿時間:2021-05-21 21:39:30 RSSフィード2021-05-21 21:00 分まとめ(43件)

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IT	ITmedia 総合記事一覧	[ITmedia ビジネスオンライン] 特許技術によるAI自動本人認証システム「オンライン・フェイス」が本格稼働　学習時の受講態度を可視化	https://www.itmedia.co.jp/business/articles/2105/21/news142.html	itmedia	2021-05-21 20:14:00
IT	MOONGIFT	SmartLink - シンプルな短縮URLソフトウェア	http://feedproxy.google.com/~r/moongift/~3/qtocWdJt0gM/	heroku	2021-05-21 21:00:00
python	Pythonタグが付けられた新着投稿 - Qiita	Fortranからnumpy配列を読み書きしたい！: forpyの利用その3	https://qiita.com/cometscome_phys/items/adf2b78b23a52941b0a3	numpy配列をFortran配列にする場合には、callpyで返ってきたPythonオブジェクトを一旦castでnumpy配列にしてから、getdataをしなければならないことに注意してください。	2021-05-21 20:59:29
python	Pythonタグが付けられた新着投稿 - Qiita	引数として渡した配列に要素を追加したときの挙動まとめ(python)	https://qiita.com/alphajinsei/items/532373af167e46421a77	OKなパターン関数呼び出し後もarrayの中身が書き変わらないこれを回避するには、言い換えれば、関数内での配列書き換えを外に影響しないようにするためには、要は関数内でarrayのコピーを作ってから作業を始めれば良い。	2021-05-21 20:24:01
js	JavaScriptタグが付けられた新着投稿 - Qiita	Automation 360上でJavaScriptを使ってUnix時間を取得する	https://qiita.com/zamaezaaa/items/bd149b873174e97a919c	Automation上でJavaScriptを使ってUnix時間を取得するAPIを叩くときにちょっと必要になったので、自分のメモを兼ねて貼っておきます。	2021-05-21 20:48:31
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	onCLickで削除処理を実装したい	https://teratail.com/questions/339641?rss=all	onCLickで削除処理を実装したい登録されている名前をクリックすると削除のAlertDialogが表示され、AlertDialog内の削除「OK」のボタンを押すとRcyclerView内のクリックした名前が削除される処理を書きたいのですがどうやって書けばいいわからず立ち往生しています。	2021-05-21 20:54:32
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	GASで抽出したGmailの本文の特定の文字以降を抽出させたい	https://teratail.com/questions/339640?rss=all	GASで抽出したGmailの本文の特定の文字以降を抽出させたい前提・実現したいこと現在該当のソースコードのとおり、GASを利用し、constnbspqueryにて特定の件名のメールに対して、メール本文・送信者、日時などを抽出しているが、メール本文の中の特定の文字・数字を抽出したい。	2021-05-21 20:30:39
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	python1年生という教材を使って勉強中です。 ファイルダイアログを使って画像を表示させたいです。	https://teratail.com/questions/339639?rss=all	python年生という教材を使って勉強中です。	2021-05-21 20:17:03
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	日付と日数から何日後かの日付計算をしたい	https://teratail.com/questions/339638?rss=all	日付と日数から何日後かの日付計算をしたい前提・実現したいこと日付を入力したらその日分を加算したい。	2021-05-21 20:09:08
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	pyenv globalでバージョンが切り替わらない	https://teratail.com/questions/339637?rss=all	pyenvglobalでバージョンが切り替わらない前提・実現したいこと↑こちらを参考にubuntuにpyenvをインストールしました。	2021-05-21 20:05:20
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	JavaScriptのコードが、safariでfunctionを使用した時のみエラーになるので理由が知りたいです	https://teratail.com/questions/339636?rss=all	以下質問内容になります。	2021-05-21 20:03:35
Ruby	Rubyタグが付けられた新着投稿 - Qiita	ExecJS::ProgramErrorに悩まされる	https://qiita.com/ogixxx/items/4f59a3d3bbea2c55a11f	ExecJSProgramErrorに悩まされる現場で使えるRubyonRails速習実践ガイドをすすめていて、ChapterPのルーティングを書き換え、サーバを停止・再起動してブラウザでlocalhostにアクセスした際、ExecJSProgramErrorがでて困った。	2021-05-21 20:45:12
Ruby	Rubyタグが付けられた新着投稿 - Qiita	[Rails]検索フォームでの検索機能/複数ワードでの検索を実装する	https://qiita.com/kei-kun1960/items/6f82d3ede76031dc7795	Rails検索フォームでの検索機能複数ワードでの検索を実装する記事の概要前回の記事の続き。	2021-05-21 20:22:54
AWS	AWSタグが付けられた新着投稿 - Qiita	初めてのAWSでNoCredentialsError: Unable to locate credentialsが出たのでDockerを設定する	https://qiita.com/Sicut_study/items/3a4a0f107462a8d9487a	DockerfileENVAWSACCESSKEYIDltアクセスキーIDgtENVAWSSECRETACCESSKEYltシークレットアクセスキーgtこの状態で先ほどのエラーが出たコードを実施したところ成功しました。	2021-05-21 20:24:56
Docker	dockerタグが付けられた新着投稿 - Qiita	初めてのAWSでNoCredentialsError: Unable to locate credentialsが出たのでDockerを設定する	https://qiita.com/Sicut_study/items/3a4a0f107462a8d9487a	DockerfileENVAWSACCESSKEYIDltアクセスキーIDgtENVAWSSECRETACCESSKEYltシークレットアクセスキーgtこの状態で先ほどのエラーが出たコードを実施したところ成功しました。	2021-05-21 20:24:56
Docker	dockerタグが付けられた新着投稿 - Qiita	初めてDockerに.envを導入するときに読む記事	https://qiita.com/Sicut_study/items/84a079f495a3b5419758	ReadmemdAWSSDKを利用する場合envというファイルを作成するenvtemplateの内容をコピーしてenvに貼り付ける自分のアクセスキーIDとシークレットアクセスキーを該当の箇所に記述するおわりにDockerのenvと環境変数の扱い方についてまとめてみました。	2021-05-21 20:24:04
golang	Goタグが付けられた新着投稿 - Qiita	Go言語でパスパラメータの値を構造体に自動代入させる	https://qiita.com/ryuken/items/bc2375ed5f9a273cc8db	jsonパッケージを利用してparseする方法があるが・・・このmapの中身を構造体にparseする方法も実はあって、jsonパッケージを使えば簡単にできてしまします。	2021-05-21 20:04:43
Ruby	Railsタグが付けられた新着投稿 - Qiita	ExecJS::ProgramErrorに悩まされる	https://qiita.com/ogixxx/items/4f59a3d3bbea2c55a11f	ExecJSProgramErrorに悩まされる現場で使えるRubyonRails速習実践ガイドをすすめていて、ChapterPのルーティングを書き換え、サーバを停止・再起動してブラウザでlocalhostにアクセスした際、ExecJSProgramErrorがでて困った。	2021-05-21 20:45:12
Ruby	Railsタグが付けられた新着投稿 - Qiita	[Rails]検索フォームでの検索機能/複数ワードでの検索を実装する	https://qiita.com/kei-kun1960/items/6f82d3ede76031dc7795	Rails検索フォームでの検索機能複数ワードでの検索を実装する記事の概要前回の記事の続き。	2021-05-21 20:22:54
技術ブログ	Developers.IO	目指せ世界最速！Alteryx Virtual Grand Prix #AlteryxInspire	https://dev.classmethod.jp/articles/alteryx-inspire-2021-grand-prix/	alter	2021-05-21 11:13:35
海外TECH	Ars Technica	The Ferrari Portofino M, reviewed	https://arstechnica.com/?p=1765505	entry	2021-05-21 11:30:41
海外TECH	DEV Community	JS interview in 2 minutes / pure vs impure functions	https://dev.to/kozlovzxc/js-interview-in-2-minutes-pure-vs-impure-functions-22om	JS interview in minutes pure vs impure functionsQuestion Explain the difference between pure and impure functions What are the side effects Quick answer A pure function is a function that returns the same result for the same arguments also this function doesn t have any side effects The side effect is then function modify any data outside of its current scope Longer answer We can start with side effects basically this means that if you have some environment and you run a function with a side effect something will be changed by this function in this environment Possible examples are writing to file displaying something to the user making HTTP requests modifying global variables emitting events off the top If I understand wiki definition of side effects this means that reading environment doesn t actually count as a side effect does it Is function which reads current time function with side effects As for repeatable results it is simpler to just give an example let add a b gt a b let mult a b gt a b let getProp name gt obj gt obj name All these functions are repeatable because they are providing the same result over the same arguments Btw there are no side effects gt they are pure Real life applications Pure functions significantly simplify testing and debugging also helps to reuse code easier If you don t depend on the environment it will be ridiculously easy to write tests Same for reusability everyone should prefer just using something over setting the environment gt using something gt cleaning the environment Can you spot the issue here let headers some regular headers function getAuthData headers push Authorization token return http get data headers function externalService return http get headers let data getAuthData let data externalService Resources wiki pure functinoswiki side effectOther posts JS interview in minutes ClosureJS interview in minutes Currying JS interview in minutes PromiseBtw I will post more fun stuff here and on Twitter Let s be friends	2021-05-21 11:40:55
海外TECH	DEV Community	How to get the current directory in python?	https://dev.to/hrishikesh1990/how-to-get-the-current-directory-in-python-4k6p	How to get the current directory in python In this python tutorial we look at how you can get the current working directory in Python and how you can change the working directory This tutorial is a part of our initiative at Flexiple to write short curated tutorials around often used or interesting concepts However in case you are here only for the solution use this link Table of ContentWhat are directories and how do they work Python get current directoryPython change directoryLimitations and Caveats What are directories and how do they work In case you are new to programming directories are nothing but folders These directories are present inside a root folder eg C or D and each directory could contain files or subdirectories and so on And to retrieve a file from you would need to know the exact path to reach the file in windows you can view a particular file path by right clicking the file General Location Furthermore when you run a python script the current directory is set to the location of the script And while trying to run another script or while handling files in python the Current Working Directory CWD is important as python would not be able to access the files if there aren t in the CWD It is in these scenarios that the python get current directory helps you know which directory you are in currently Python get current directoryThe python get current directory would help you know which directory you are currently in to do this we use the OS module to interact with the operating system and we use the os getcwd method to return the path of the current directory Syntax of os getcwd os getcwd Code for python get current directory importing the os moduleimport os to get the current working directorydirectory os getcwd print directory The output way may vary depending on the directory you are in but it would root folder eg D and the directory prefixed by a Python change directorySimilar to python get current directory we use the os module to change the current directory as well We make use of the chdir methods to change the directory Uses of this would again be to change the current directory in order to retrieve relevant files Syntax of chdir os chdir path Parameters path The path to the new directory Code to change current directory Let s say i wanted to change the directory to a directory called freelancer inside the flexiple import osos chdir C freelancer flexiple Limitations and CaveatsThe python get current directory method only return the current working directory in case you want the entire path use os path realpath file Unlike the python get current directory the change directory requires a parameter that needs to be a directory and if not python return a NotADirectoryErrorIf the directory does not exist then a FileNotFoundError is returned And in case the user lacks the necessary permissions to access the directory a PermissionError is returned Do let me know your thoughts in the comment section below Happy coding	2021-05-21 11:23:42
海外TECH	DEV Community	Interpreting Free Monads	https://dev.to/choc13/interpreting-free-monads-3l3e	Interpreting Free MonadsIn the last post in this series we grokked Free Monads and saw that they gave us a way to neatly build an abstract representation of a computation using only data That s all well and good when we re writing our domain model but eventually we need to actually do some real computing to run the side effects and produce the results In this post we ll learn how to write interpreters for free monads first an interpreter to run the computation in the context of our application and then a different interpreter that lets us write “mockless unit tests for our domain operations Recap Let s quickly remind ourselves of the problem we were solving last time We wanted to write a chargeUser function which looked up a user by their id then charged their card the specified amount and finally emailed them a receipt if they had an email address on their profile Here s the domain model we were using type EmailAddress EmailAddress of stringtype Email To EmailAddress Body string type CreditCard Number string Expiry string Cvv string type TransactionId TransactionId of stringtype UserId UserId of stringtype User Id UserId CreditCard CreditCard EmailAddress EmailAddress option We then wrote a discriminated union to represent the operations we needed to perform as part of the chargeUser computation which looked like this type ChargeUserOperation lt next gt LookupUser of UserId User gt next ChargeCreditCard of float CreditCard TransactionId gt next EmailReceipt of Email unit gt next static member Map op f match op with LookupUser x next gt LookupUser x next gt gt f ChargeCreditCard x next gt ChargeCreditCard x next gt gt f EmailReceipt x next gt EmailReceipt x next gt gt f Finally with the help of some smart constructors we could write the abstract version of chargeUser which builds a free monad to represent the computation we want to eventually perform r nuget FSharpPlus open FSharpPlusopen FSharpPlus Datalet lookupUser userId LookupUser userId id gt Free liftFlet chargeCreditCard amount card ChargeCreditCard amount card id gt Free liftFlet emailReceipt email EmailReceipt email id gt Free liftFlet chargeUser amount float userId UserId monad let user lookupUser userId let transactionId chargeCreditCard amount user CreditCard match user EmailAddress with Some emailAddress gt do emailReceipt To emailAddress Body TransactionId transactionId return transactionId None gt return transactionId I ve made use of FSharpPlus here for a couple of things The monad computation expression which is just a generic computation expression that works for any monad The Free data type which uses the names Roll and Pure in place of the names Operation and Return that we made up last time It also provides us with Free liftF meaning lift functor which lifts the operation functor to a free monad As we discovered last time as long as our operations are mappable we can always lift them into a free monad A trivial interpreterOur goal previously when writing the domain model was to remove and real calls to infrastructure functions from the domain model We re now going to shift focus to writing the application layer where we want to actually do the real work The application layer is responsible for receiving external requests e g via a REST API and then calling the domain model to process them It should be able to wire up the actual infrastructure in order to implement the operations like LookupUser So our job here is to take the abstract data structure output from chargeUser in the domain model and turn it into a real computation with real side effects this is the job of the interpreter What we need to do is write a function called interpret which goes from Free lt ChargeUserOperation lt TransactionId gt TransactionId gt to TransactionId That perhaps seems a bit tricky so let s start by writing out chargeUser long hand to see more clearly what it is that we need to interpret let chargeUser amount userId Roll LookupUser userId fun user gt Roll ChargeCreditCard amount user CreditCard fun transactionId gt match user EmailAddress with Some emailAddress gt Roll EmailReceipt To emailAddress Body TransactionId transactionId fun gt Pure transactionId None gt Pure transactionId Hopefully the strategy for writing interpret is clearer now that we ve removed the syntactic sugar of the monad computation expression We can see that we re going to need to recursively pattern matching on Roll operation until we hit a Pure value case Let s give that a try let rec interpret chargeUserOutput TransactionId match chargeUserOutput with Roll op gt match op with LookupUser userId next gt let user some hard coded user value user gt next gt interpret ChargeCreditCard amount card next gt TransactionId gt next gt interpret EmailReceipt email next gt gt next gt interpret Pure x gt xJust as we d planned if we match on a Roll case then we unwrap a ChargeUserOperation which we can then pattern match on again When we match on an operation the only sensible thing we can do is call next with the type of input it s expecting for example next in LookupUser wants a User This generates us another Free lt gt so we recursively call interpret to interpret that result until we hit a Pure case and we can just return the result Note if you want to play with this code then you ll actually need to write match Free run chargeUserOutput due to the way FSharpPlus has implemented Free internally In this example we ve just hardcoded a bunch of values so we re still not doing any real work but we can at least test this in the F REPL now to see what happens gt chargeUser UserId gt interpret val it TransactionId TransactionId Great it s produced the hard coded TransactionId One thing that stands out from this trivial implementation of interpret is that the outer pattern match doesn t depend on the type of operation at all So let s see if we can refactor interpret such that it works for any type of operation let rec inline interpret interpretOp freeMonad match freeMonad with Roll op gt let nextFreeMonad op gt interpretOp interpret interpretOp nextFreeMonad Pure x gt xIn the Roll case we now delegate the job of interpreting the operation to the interpretOp function Calling this with an op returns the nested callback another free monad which we can then pass back into interpret As an example let s write out interpretChargeUserOp which is just the inner pattern match from our very first interpret function above let interpretChargeUserOp op match op with LookupUser userId next gt let user some hard coded user value user gt next ChargeCreditCard amount card next gt TransactionId gt next EmailReceipt email next gt gt nextThis is nice because we ve now got a universal function for interpreting any free monad We just have to supply it with a function for interpreting our use case specific operations We can interpret the free monad produced by chargeUser in the F REPL like this now gt chargeUser UserId gt interpret interpretChargeUserOp val it TransactionId TransactionId To make this more concrete let s step through what happens when we interpret the first operation The interpret function sees Roll LookupUser so it matches on Roll It then asks interpretChargeUserOp to deal with LookupUser which it handles through its pattern matching In our trivial example this just passes a hard coded user to next and we know from writing chargeUser out long hand that next will be Roll ChargeCreditCard So when control returns to interpret it will recursively pass Roll ChargeCreditCard back into itself along with the same interpretChargeUserOp function This will continue until it finds an operation whose continuation is just Pure If you ve followed that then you ve grokked it We can now move on to writing a proper interpreter for our application A real world interpreterEnough of all of this abstract nonsense we ve got an application to ship So let s get stuck in and write an actual interpreter that will do something useful We ll assume we have the following infrastructure code already defined elsewhere in some appropriate projects or libraries module DB let lookupUser userId async Create a DB connection Query the DB for the user Return the user module PaymentGateway let chargeCard amount card async Perform an async operation to charge the card Return the transaction id module EmailClient let send email async send the email With these already written writing the interpreter for our operations is a straight forward job let interpretChargeUserOp op ChargeUserOperation lt a gt Async lt a gt match op with LookupUser userId next gt async let user DB lookupUser userId return user gt next ChargeCreditCard amount card next gt async let transactionId PaymentGateway chargeCard amount card return transactionId gt next EmailReceipt email next gt async do EmailClient send email return gt next We can see from the type of interpretChargeUserOp that we re turning each domain operation into an Async operation which is exactly the separation that we wanted to achieve when we set out on our free monadic voyage Our domain model doesn t even need to know that in reality the operations are going to be async the only requirement is that they re monadic The application is free to choose the monad it actually wants to work with it could just have easily have used Task We re nearly home and dry we just need to make sure this produces the correct result We try and write chargeUser UserId gt interpret interpretChargeUserOp but the compiler says no What s happened If we look at the signature of interpret more closely we ll see that it s expecting interpretOp to return a Free lt gt The problem is that we re now returning Async lt gt from interpretChargeCardOp In general we re going to want to interpret our operations into other monads such as Async Task State etc rather than just as plain values because these operations are going to be performing side effects So we need to make a small change to interpret what we now desire is for it to have the following signature let rec inline interpret interpretOp Functor lt T gt gt Monad lt T gt freeMonad Free lt Functor lt U gt U gt Monad lt U gt This is saying that given some function that can turn functors our operation is a functor that contain a value of type T into some Monad that contains the same type T then we can use this to convert a free monad based on these operations into a different monad In order to implement this we re going to have to fix the Roll case by this time unwrapping the monad produced by interpretOp before passing it back in to the recursive call to interpret let rec inline interpret interpretOp Functor lt T gt gt Monad lt T gt freeMonad Free lt Functor lt U gt U gt Monad lt U gt match freeMonad with Roll op gt monad let nextFreeMonad interpretOp op return interpret interpretOp nextFreeMonad Pure x gt monad return x We ve also had to change Pure slightly so that it basically lifts the value up into the target monad type too For instance if we were trying to convert the free monad to an async computation you could read the above like this instead let rec inline interpretAsync interpretOp Functor lt T gt gt Async lt gt freeMonad Free lt Functor lt U gt U gt Async lt gt match freeMonad with Roll op gt async let nextFreeMonad interpretOp op return interpretAsync interpretOp nextFreeMonad Pure x gt async return x Finally let s make sure this new interpreter works now gt chargeUser UserId gt interpret interpretChargeUserOp gt Async RunSynchronously val it TransactionId TransactionId You ve just discovered Free fold What we ve been calling interpret is actually the fold function for the Free data type It replaces all of the abstract Roll operation elements of the data structure with the results of calling the function f that runs the operation function in a particular monad like Async We ve seen here how we can use it in the application layer to turn the abstract domain computation into real calls to the database etc The fun doesn t end there though because we ve decoupled the what from the how we can interpret our domain model in lots of different ways let s take a look at another useful way of folding it A test interpreter Let s imagine that we want to verify that chargeUser only sends an email if the user has an email address How can we test this Well we can just write a different interpreter of course one that lets us track how many times the EmailReceipt case was present in the computation We re going to need our interpreter to do a couple of things Return a specific User object from LookupUser so that we can control whether or not there is an EmailAddress on the profile Count the number of times EmailReceipt is present in the computation Taking care of point is easy because we already saw in the first trivial interpreter we wrote how to return hard coded values What about point though Well we know that we can interpret our free monad as any other monad so why not pick one that lets us track some state where that state is a counter for the number of times EmailReceipt is called For this we can use the Writer monad which is just a monad that lets us update some value that gets passed through the entire computation Using that our test could look like this module Tests let shouldOnlySendReceiptWhenUserHasEmailAddress user let output chargeUser UserId gt Free fold function LookupUser next gt monad return user gt next ChargeCreditCard next gt monad return TransactionId gt next EmailReceipt next gt monad do Writer tell return gt next Writer exec output For the LookupUser operation we just pass the user argument that was passed to this test function into next That allows us to have precise control over the User that is used in a particular test run Interpreting ChargeCreditCard is boring here we just hard code a TransactionId and pass it to next because we re not interested in that part for this test In EmailReceipt we use the Writer monad to increment the counter to track the fact that a call to EmailReceipt has been made Finally we call Writer exec output to run the computation with an initial count of Let s give this a try in the REPL and see what results we get gt let userNoEmail Id UserId EmailAddress None CreditCard Number Expiry Cvv gt Tests shouldOnlySendReceiptWhenUserHasEmailAddress userNoEmail val it int When the user doesn t have an email address the call count is gt let userWithEmail Id UserId EmailAddress Some EmailAddress a example com CreditCard Number Expiry Cvv gt Tests shouldOnlySendReceiptWhenUserHasEmailAddress userWithEmail val it int When the user does have an email address the call count is But I don t need a monad ‍ ️Sometimes particularly when testing you don t need to interpret the operations into a monad For example you might just want to check the output of the computation based on some inputs or based on the data returned from the call to the database In that case you can use the Identity monad Let s see what that looks like let shouldReturnTransactionIdFromPayment user let output chargeUser UserId gt Free fold function LookupUser next gt monad return user gt next ChargeCreditCard next gt monad return TransactionId gt next EmailReceipt next gt monad return gt next output gt Identity run What did we learn We ve seen that free monads provide an excellent means of decoupling the what from the how They allow us to write our domain model computations declaratively and leave the interpretation of how that should be done up to another layer of the application In this post we learnt that we can use fold to interpret a free monad and all we have to do is supply it with a function to interpret our particular operations into some target monad This decoupling is particularly powerful when it comes to testing our domain models because it gives us precise control over the functions being tested We don t have to worry about async calls in our test suite because we can choose to interpret the computation synchronously in the tests It even eliminates the need for any mocking frameworks because it s trivial for us to check the number invocations for a particular operation or verify that particular arguments were supplied to a function Free monads might be abstract but so should our domain models and the two go hand in hand very nicely	2021-05-21 11:13:11
海外TECH	DEV Community	React: ContextAPI as a State solution? [ UPDATED ]	https://dev.to/sumodevelopment/react-contextapi-as-a-state-solution-updated-5a2j	React ContextAPI as a State solution UPDATED Updated from Previous Article React ContextAPI as a State solution Dewald Els・May ・ min read react state javascript experiments ️Problems with Previous ApproachAlthough the approach taken in the previous article seemed to work fine the most severe problem was that any component that used the AppContext would re render Even if it was using an unrelated state object from the Context Therefore I set out to fix this SolutionI ve updated to solution to use multiple contexts one for each part of the state I then created a AppContext which brought together all the Contexts and wrapped that around my my application ‍The codeYou can get a copy of the code on Github I ve created a new branch which you can find here Github Separated State Creating separate ContextsThe first order of business is to create a new Context for each part of my state You will see in each of the code snippets that there are two main parts The Provider Component The Context Provider is used as a Higher Order Component and provides the state value and setter as an Object to the value This allows the developer to desctructure only the state or setter in a Component Custom Hook to access the Context s stateThe custom hook allows easy access to the state and avoids the import of both useContext and MoviesContext in any component that wishes to use the movies state The Movies Contextimport createContext useContext useState from react const MoviesContext createContext export const useMovies gt return useContext MoviesContext export const MoviesProvider children gt const movies setMovies useState return lt MoviesContext Provider value movies setMovies gt children lt MoviesContext Provider gt context MoviesContext js The Profile Contextimport createContext useContext useState from react const ProfileContext createContext null export const useProfile gt return useContext ProfileContext export const ProfileProvider children gt const profile setProfile useState null return lt ProfileContext Provider value profile setProfile gt children lt ProfileContext Provider gt context ProfileContext js The UiLoading Contextimport createContext useContext useState from react const UiLoadingContext createContext false export const useUiLoading gt return useContext UiLoadingContext export const UiLoadingProvider children gt const uiLoading setUiLoading useState false return lt UiLoadingContext Provider value uiLoading setUiLoading gt children lt UiLoadingContext Provider gt context UiLoadingContext js The new AppContextGiven that I now have three separate contexts rather than bloating the index js file with multiple providers I decided to create a AppContext component to group all the Providers together As far as I can tell the order here does not make a difference Feel free to correct this in the comments and I will update the article import ProfileProvider from ProfileContext import MoviesProvider from MoviesContext import UiLoadingProvider from UiLoadingContext export const AppProvider children gt return lt ProfileProvider gt lt MoviesProvider gt lt UiLoadingProvider gt children lt UiLoadingProvider gt lt MoviesProvider gt lt ProfileProvider gt context AppContext js Using the Context s StateThanks to the custom hook in each context it is terrifically easy to gain access to both the state value and or setter If you would want to update the profile and ONLY have access to the setter you can write the following code const Login gt console log Login render const setProfile useProfile const onLoginClick gt setProfile username birdperson Login jsLogin Login jsThe big Win here is that ONLY components using the profile context will now re render This is a stark contrast to the previous article s approach where all components using the AppContext would re render even if it wasn t accessing the profile state If you need to access both the state and the setter you can use the custom hook again like this const movies setMovies useMovies And again only components using the MoviesContext would re render when the setMovies setter is invoked leaving other components untouched ConclusionUsing Context is a great way to share state in small applications but comes with some Gotchas if you re not clear on how the ContextAPI works This is been a great learning experience and thanks again for the messages pointing out the improvements to be made Thanks for reading	2021-05-21 11:02:09
Apple	AppleInsider - Frontpage News	How to use HomePod for all TV audio with Apple TV 4K	https://appleinsider.com/articles/21/05/21/how-to-use-homepod-for-all-tv-audio-with-apple-tv-4k?utm_medium=rss	How to use HomePod for all TV audio with Apple TV KThe new Apple TV K can relay any audio from a compatible TV set to a pair of HomePods without requiring users to be watching via the Apple set top box Here s how to do itThe new Apple TV K has an unexpected audio bonusAs the new Apple TV K begins to arrive for pre order customers a new support document has revealed that its audio capabilities have an unexpected extra As well as being able to send audio to the HomePod as it has before the new set top box can also receive audio from a TV set and relay it to those smart speakers Read more	2021-05-21 11:46:45
海外TECH	Engadget	NASA, ESA and JAXA want to figure out COVID-19's environmental effects	https://www.engadget.com/nasa-esa-jaxa-covid-19-environmental-effects-115033335.html	NASA ESA and JAXA want to figure out COVID x s environmental effectsNASA the European Space Agency and the Japan Aerospace Exploration Agency JAXA are hosting a hackathon to figure out COVID s environmental effect	2021-05-21 11:50:33
海外TECH	Engadget	The Morning After: Cleaning with the laser-equipped Dyson V15 Detect	https://www.engadget.com/the-morning-after-cleaning-with-the-dyson-v15-detect-112528577.html	The Morning After Cleaning with the laser equipped Dyson V DetectToday s headlines Overwatch will change from six to five person teams Snap unveils all new Spectacles with built in augmented reality and Belkin s Soundform Connect dongle adds AirPlay to any speaker	2021-05-21 11:25:28
海外ニュース	Japan Times latest articles	IOC suggests Olympics can be held even if Tokyo is under a state of emergency	https://www.japantimes.co.jp/news/2021/05/21/national/ioc-reassure-olympics-covid/	IOC suggests Olympics can be held even if Tokyo is under a state of emergency I can say it s now clearer than ever that these games would be safe for everyone participating and importantly safe for the people of Japan	2021-05-21 20:48:48
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ニュース	BBC News - Home	Covid: What's the roadmap for lifting lockdown?	https://www.bbc.co.uk/news/explainers-52530518	wales	2021-05-21 11:48:48
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