投稿時間:2021-06-06 09:16:42 RSSフィード2021-06-06 09:00 分まとめ(19件)

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Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	HTML 　文字収まりの原因がわかりません。	https://teratail.com/questions/342414?rss=all	HTML文字収まりの原因がわかりません。	2021-06-06 08:56:59
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	自然言語処理入門書でエラーがでる件	https://teratail.com/questions/342413?rss=all	自然言語処理入門書でエラーがでる件打ち消し線nbsp前提・実現したいことstepで踏破自然言語処理アプリケーション開発入門でpythonを勉強しています。	2021-06-06 08:53:57
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	pyxelを実行できない	https://teratail.com/questions/342412?rss=all	pyxelを実行できない前提・実現したいことpyxelのファイルを実行すると下のようなエラーメッセージが出ます。	2021-06-06 08:47:27
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	COBOLで入力レコードの値が定義した配列に上手く入らない	https://teratail.com/questions/342411?rss=all		2021-06-06 08:27:22
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Vue vs React について	https://teratail.com/questions/342410?rss=all	VuevsReactについてVuenbspvsnbspReactnbspについてあくまで、VueのCompositionnbspAPInbspとReactのreactnbsphooksでの比較だが、なぜ、reactの方が、世界的に倍ほどのシャアがあり、まだまだシャアが伸び続けているのか理解できないです。	2021-06-06 08:26:30
Ruby	Rubyタグが付けられた新着投稿 - Qiita	[Rails]field_for 配下の各オブジェクトを取得する方法	https://qiita.com/hiromiya0628/items/452e0e9d274c7a6c54f6	Railsfieldfor配下の各オブジェクトを取得する方法課題fieldsfor配下の各オブジェクトを取得する方法を知らなかったのでメモ。	2021-06-06 08:15:17
Ruby	Railsタグが付けられた新着投稿 - Qiita	初めてのローカル環境構築（MacでHomebrewを経由しRailsを導入する）	https://qiita.com/Shuhei_Nakada/items/7081a2a33797ed953e34	railsvこれで、rubyとrailsがインストールできました良かった良かったMySQLのインストールから設定まで続いて、データベースの設定していきます。	2021-06-06 08:35:53
Ruby	Railsタグが付けられた新着投稿 - Qiita	[Rails]field_for 配下の各オブジェクトを取得する方法	https://qiita.com/hiromiya0628/items/452e0e9d274c7a6c54f6	Railsfieldfor配下の各オブジェクトを取得する方法課題fieldsfor配下の各オブジェクトを取得する方法を知らなかったのでメモ。	2021-06-06 08:15:17
海外TECH	DEV Community	Design Patterns In JavaScript	https://dev.to/twinfred/design-patterns-in-javascript-1l2l	Design Patterns In JavaScriptI was recently asked by a developer friend of mine what design patterns I use in my job The question threw me off a bit because I didn t actually know the answer even though I know that there are definitely patterns that I ve used Do those patterns have names And why are the patterns I have been using better than others For today s post I will be writing down my notes and thoughts as I learn about a variety of design patterns and how to implement them in JavaScript Feel free to join me on my journey in this post or make fun of my noob ness as I discover something I feel like I should have learned already Better late than never right FYI One of my primary resources for this post was this blog post from Lambda Test What is a design pattern According to Wikipedia a software design pattern is A general reusable solution to a commonly occurring problem within a given context in software design It is not a finished design that can be transformed directly into source or machine code Rather it is a description or template for how to solve a problem that can be used in many different situations Design patterns are formalized best practices that the programmer can use to solve common problems when designing an application or system The Lambda Test article also pointed out that they represent time tested solutions and best practices adopted by object oriented software developers over time JavaScript Design PatternsSourceAccording to Lambda Test not all of the patterns are necessary for use in JavaScript since there are native features that implement them for us so I will only be discussing a select group of design patterns for this post Feel free to drop me a comment if you want me to add one that I skipped over NOTE All of the quoted definitions below come from the Software Design Patterns entry on Wikipedia Constructor Builder Pattern Creational DesignSeparate the construction of a complex object from its representation allowing the same construction process to create various representations Ok so I ve definitely written JavaScript code using the Constructor design pattern before I guess I just thought it was a feature of classes in JavaScript I never knew that it was considered a design pattern class Person constructor name age mother this name name this age age this mother mother const tim new Person Tim null const tina new Person Tina null tim mother tina console log tim const grandma new Person Sherry null tina mother grandma console log tim Factory Pattern Creational DesignDefine an interface for creating a single object but let subclasses decide which class to instantiate Factory Method lets a class defer instantiation to subclasses So based on the way the pattern is implemented in the Lambda Test post it seems like the name is perfect It is literally a pattern where you set up a single function that can take a variety of arguments to return the appropriate object It s like asking a clothing factory for a shirt they give you a shirt Ask for pants they give you pants Ask for shoes you get shoes And each of those objects has it s own functionality function animalFactory this createAnimal function animalType let animal switch animalType case dog animal new Dog break case cat animal new Cat break case horse animal new Horse break default animal new Monkey break return animal const Dog function this makeSound gt console log woof woof const Cat function this makeSound gt console log prrr prrr meow const Horse function this makeSound gt console log neeeighhh const Monkey function this makeSound gt console log ooooh ahh oooh oooh const factory new animalFactory const jojo factory createAnimal dog jojo makeSound const smokey factory createAnimal cat smokey makeSound const princess factory createAnimal horse princess makeSound const kong factory createAnimal monkey kong makeSound Prototype Pattern Creational DesignSpecify the kinds of objects to create using a prototypical instance and create new objects from the skeleton of an existing object thus boosting performance and keeping memory footprints to a minimum I haven t played around with prototyping very much so I m excited to dig into this more especially since I know it s an awesome feature of JavaScript In all honesty this one confused me a lot at first until I re read the section in the Lambda Test article and realized it s all about cloning Once I played around with the implementation below I was able to figure it out and really understand it const macBook color silver turnOn console log turning on turnOff console log turning off Proper prototype cloningconst myComputer Object create macBook owner value Tim console log myComputer proto macBook Not a prototype copyconst newComputer macBook owner John console log newComputer proto macBook macBook power USB C The protoype gets the new value for power console log myComputer power But the non prototype doesn tconsole log newComputer power Singleton Pattern Strict Pattern Creational DesignEnsure a class has only one instance and provide a global point of access to it So this one makes sure that only one instance exists If something attempts to make another it simply returns a reference to the one that already exists Easily understood const Database function let instance function createDatabaseInstance return new Object Database Instance function getDatabaseInstance if instance instance createDatabaseInstance return instance return getDatabaseInstance const databaseInstance Database getDatabaseInstance const databaseInstance Database getDatabaseInstance console log databaseInstance databaseInstance Adapter Pattern Wrapper Pattern Structural DesignConvert the interface of a class into another interface clients expect An adapter lets classes work together that could not otherwise because of incompatible interfaces The enterprise integration pattern equivalent is the translator Having lived abroad for a year the idea of an adapter is easy enough to understand It seems like it could possibly be a useful way of connecting a function from legacy code to a function in a newer part of the codebase I found this really awesome YouTube video that perfectly explains a use case for the Adapter pattern and was able to use that to create the below implementation to combine two different NPM libraries into one utility The code I wrote isn t easily copy pasted into this post so feel free to check out the code on my Github I can definitely imagine A LOT of use cases for this design pattern and actually look forward to using it to help make my code more easily maintainable in the future Probably my favorite design pattern so far Composite Pattern Structural DesignCompose objects into tree structures to represent part whole hierarchies Composite lets clients treat individual objects and compositions of objects uniformly Hey it s just nodes and components I definitely know about this design pattern One parent multiple children And those children can have multiple children It s the one to many pattern used in JSON and HTML trees And now I know the official name of the design pattern for it const Node function name this children this name name Node prototype add function child this children push child return this recursive console log of what s inside of the treeconst log root gt if root return console log console log Node root name console log root root children forEach child gt if child children length log child const init gt const tree new Node root const left right new Node left new Node right const leftleft leftright new Node leftleft new Node leftright const rightleft rightright new Node rightleft new Node rightright tree add left add right left add leftleft add leftright right add rightleft add rightright log tree init Module Pattern Structural DesignGroup several related elements such as classes singletons methods globally used into a single conceptual entity This design pattern reminds me of when I learned Java Getting to give your function private functions and variables while only exposing the functions and variables that are necessary I have definitely used this design pattern multiple times in my career Good to know it has a name const userApi gt private variables const users private function const addUser name gt users push name return users users length private function const getAllUsers gt return users private function const deleteUser name gt const userIndex users indexOf name if userIndex lt throw new Error User not found users splice userIndex private function const updateUser name newName gt const userIndex users indexOf name if userIndex lt throw new Error User not found users userIndex newName return users userIndex return public functions add addUser get getAllUsers del deleteUser put updateUser const api userApi api add Tim api add Hina api add Yasmeen api add Neeloo console log api get api del Yasmeen console log api get api put Tim Tim Winfred console log api get Decorator Pattern Structural DesignAttach additional responsibilities to an object dynamically keeping the same interface Decorators provide a flexible alternative to subclassing for extending functionality Ok this one is fun and easy to understand I can set up a function to give an object common functionality and traits but then I can decorate each individual instance of that object with it s own functionality and traits I can definitely see myself using this at some point in the future const Animal function type this type type dog const dog new Animal dog const cat new Animal cat dog bark function console log woof woof return this cat meow function console log meow meooooooow return this dog bark cat meow Facade Pattern Structural DesignProvide a unified interface to a set of interfaces in a subsystem Facade defines a higher level interface that makes the subsystem easier to use I m actually fairly familiar with the use of a facade I ve been leveraging a pre built facade on one of the projects I am currently working on at work It is even imported with the name facade but I had no idea that this was a design pattern I found this video on JavaScript facade design that was really helpful The guy presenting in that video has a LOT of really helpful videos import axios from axios function getUsers return facade get function getUserById id return facade get id const facade get function url params return axios url params method GET then res gt res data async function getData try console time getUsers took const users await getUsers console timeEnd getUsers took console log There are users length users console time getUserById took const user await getUserById console timeEnd getUserById took console log user catch error console log error getData Proxy Pattern Structural DesignProvide a surrogate or placeholder for another object to control access to it As a Magic The Gathering player this one makes sense in theory Don t use the expensive card when you can use a proxy card instead I found this highly rated YouTube video about the Proxy Design Pattern and how it can be used in JavaScript to create a cache to save time and reduce the number of times you have to hit an external API Mock External APIfunction CryptoCurrencyAPI this getValue function coin console log Calling Crypto API to get coin price switch coin toLowerCase case bitcoin return case ethereum return case dogecoin return function CryptoCurrencyAPIProxy this api new CryptoCurrencyAPI this cache this getValue function coin if this cache coin console log The value of coin isn t stored in cache this cache coin this api getValue coin return this cache coin const proxyAPI new CryptoCurrencyAPIProxy console log proxyAPI getValue Bitcoin console log proxyAPI getValue Bitcoin console log proxyAPI getValue Ethereum console log proxyAPI getValue Ethereum console log proxyAPI getValue Dogecoin console log proxyAPI getValue Dogecoin Chain of Responsibility Pattern Behavioral DesignAvoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request Chain the receiving objects and pass the request along the chain until an object handles it This is another one of those patterns that I definitely understand in theory and can connect to a lot of real world scenarios but I can t immediately think of an implementation for coding aside from the sample given in the Lambda Test article After playing around with it a bit I actually do like this design pattern and enjoy the ease of method chaining What do you think of what I created I m not quite sure it fulfills the object definition from Wikipedia const ATM function this withdrawl function amount console log Requesting to withdrawl amount toFixed if amount console log Sorry this ATM can t dispense coins Please request another amount return const dispenseOutput chain or responsibility function function get bill dispenseOutput bill Math floor amount bill amount dispenseOutput bill bill return get get get get get get get this dispense dispenseOutput this dispense function bills console log Dispensing cash Object entries bills forEach key value gt console log Dispensing value key bills const myATM new ATM myATM withdrawl myATM withdrawl myATM withdrawl Command Pattern Behavioral DesignEncapsulate a request as an object thereby allowing for the parameterization of clients with different requests and the queuing or logging of requests It also allows for the support of undoable operations This one seems pretty easy and I really like the separation of the command object and the receiver Makes for clean code I actually was trying to create a calculator with React recently so this is the perfect solution const calculationMethods add function x y return x y subtract function x y return x y multiply function x y return x y divide function x y return x y const calculator execute function method num num if method in calculationMethods return null return calculationMethods method num num console log calculator execute add console log calculator execute subtract console log calculator execute multiply console log calculator execute divide console log calculator execute square root Observer Pub Sub Pattern Behavioral DesignDefine a one to many dependency between objects where a state change in one object results in all its dependents being notified and updated automatically My immediate thought is that this makes me think of observables in JavaScript which I haven t played around with too much at least not in a while The pub sub idea of this pattern also makes me think of websockets and Redux In my below implementation I used the example from this freeCodeCamp video that has great explaintion of the observer pattern I switch things up a bit and implemented some method chaining function Subject this observers Subject prototype subscribe function observer this observers push observer return this unsubscribe function observer const indexOfObserver this observers indexOf observer if indexOfObserver gt this observers splice indexOfObserver return this notifyObserver function observer const indexOfObserver this observers indexOf observer if indexOfObserver gt this observers indexOfObserver notify return this notifyAllObservers function this observers forEach observer gt observer notify return this function Observer name this name name Observer prototype notify function console log Observer this name has been notified const subject new Subject const observer new Observer user const observer new Observer user const observer new Observer user const observer new Observer user const observer new Observer user subject subscribe observer subscribe observer subscribe observer subscribe observer subscribe observer subject notifyObserver observer subject unsubscribe observer subject notifyAllObservers Template Method Pattern Behavioral DesignDefine the skeleton of an algorithm in an operation deferring some steps to subclasses Template method lets subclasses redefine certain steps of an algorithm without changing the algorithm s structure Ok so I definitely don t understand this based on that description haha It sounds like it s extending classes and giving the new sub class new methods but I definitely have to see if I can find a better description of this one Unlike the definition of this pattern this explanation of the Template Method Pattern from Microsoft helped me understand what is happening although they re not using JavaScript as did this blog post class HouseTemplate constructor name address this name name this address address buildHouse this buildFoundation this buildPillars this buildWalls this buildWindows console log this name has been built successfully at this address buildFoundation console log Building foundation buildPillars throw new Error You have to build your own pillars buildWalls throw new Error You have to build your own walls buildWindows console log Building windows class WoodenHouse extends HouseTemplate constructor name address super name address buildPillars console log Building pillars for a wooden house buildWalls console log Building walls for a wooden house class BrickHouse extends HouseTemplate constructor name address super name address buildPillars console log Building pillars for a brick house buildWalls console log Building walls for a brick house const woodenHouse new WoodenHouse Wooden house Maple Road const brickHouse new BrickHouse Brick house Stone Lane woodenHouse buildHouse brickHouse buildHouse Strategy Pattern Behavioral DesignDefine a family of algorithms encapsulate each one and make them interchangeable Strategy lets the algorithm vary independently from clients that use it Alright so this is the last one And thankfully it s super simple to understand thanks to the Lambda Test Article I appreciate any method that allows for DRY coding and can definitely imagine a variety of implementations for this in the future function Regal this getTicketPrice function quantity return quantity function AMC this getTicketPrice function quantity return quantity function Cinemark this getTicketPrice function quantity return quantity function TicketPrice this theaterChain this setTheaterChain function chain this theaterChain chain this calculate function quantity return this theaterChain getTicketPrice quantity const regal new Regal const amc new AMC const cinemark new Cinemark const ticketPrice new TicketPrice ticketPrice setTheaterChain regal console log ticketPrice calculate ticketPrice setTheaterChain amc console log ticketPrice calculate ticketPrice setTheaterChain cinemark console log ticketPrice calculate Final ThoughtsAnd that s all folk for now I honestly had so much of fun digging into all of these design patterns and am so happy I did I skipped over a few patterns that have ES implementations in JavaScript but overall I definitely learned a lot If you read this far I hope my journey and my code has been helpful to you See ya soon Visit my Github repo to get all of the code above in one place	2021-06-05 23:10:35
金融	生命保険おすすめ比較ニュースアンテナ waiwainews	高齢者の保険の是非	http://seiho.waiwainews.net/view/12455	newsallrightsreserved	2021-06-06 08:06:43
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LifeHuck	ライフハッカー［日本版］	雨の日の山でも余裕。モンベルのレインジャケットが抜群に快適だった	https://www.lifehacker.jp/2021/06/236068roomie-montbell-rainjacket.html	間違い	2021-06-06 08:30:00
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