投稿時間:2022-10-10 16:10:02 RSSフィード2022-10-10 16:00 分まとめ(10件)

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python	Pythonタグが付けられた新着投稿 - Qiita	metpy.unitsをxarray.DataArrayに適用するワンライナー	https://qiita.com/kasugab3621/items/cb484ecedf451425efc9	xarray	2022-10-10 15:29:24
js	JavaScriptタグが付けられた新着投稿 - Qiita	Vue.jsで文字列をBase64に変換する方法	https://qiita.com/zono345/items/50037c39bca3f3e98124	clientidclientsecret	2022-10-10 16:00:19
Ruby	Rubyタグが付けられた新着投稿 - Qiita	`a ||= 10` は `a = a || 10` じゃないよ	https://qiita.com/TomoProg/items/fde0869a1698428a9560	記事	2022-10-10 15:46:37
Linux	Ubuntuタグが付けられた新着投稿 - Qiita	Ubuntu20.04にMySQLを導入	https://qiita.com/akki-memo/items/406150bf72772d290e82	ubuntultsmysqlverubuntu	2022-10-10 15:24:06
Docker	dockerタグが付けられた新着投稿 - Qiita	Docker で Mojolicious 9 を動かす	https://qiita.com/takaya030/items/1200f0242dee4103e5e8	editionversionhvirtualbox	2022-10-10 15:54:32
海外TECH	DEV Community	How to implement singleton in JavaScript	https://dev.to/sakhnyuk/how-to-implement-singleton-in-javascript-18o	How to implement singleton in JavaScriptIn this article we will examine what is Singleton and all ways how to implement it in JavaScript Singleton is a design pattern that solves two problems It ensures that a single threaded application will have only one instance of a given class Second problem when we need to have global access point to some class instance or just a object Sometimes developers call some object as a singleton even if it resolve only one problem Here some cases when we can use singleton Global app state as single source of true Redux Mobx states managers provides a global access to stateAPI Service where we incapsulate some logic and store session or token to make a API calls Service for keeping Data base or WebSocket connection and here we can be sure we have only one connection of given singletonSo let s take a look how we can implement following pattern JavaScript export import moduleThe Singleton class itself is not a JavaScript entity or feature it is an approach or pattern that we implement in some way Everything could depend on the project the tech stack we use and even the developer s skills Generally you are able to agree when to use a particular class as a single instance without any specific prevention against duplication It could work well especially when you work alone or with a small team But in bigger teams and project you should aware about it and create your singletons without possibility to have more than one instance of a class Most primitive and simple approach to implement singleton in JavaScript is exporting your instance from module using export import syntax class ApiService export const API new ApiService and then somewhere in other files import API from api A file can contain variables logic and methods that can be exported as ready to use objects When we need such an object we simply import and use it This works well but in large projects it could make it difficult to manage fake instances of services for tests or someone could import raw class ApiService and create a second instance In spite of its primitive nature this approach is still used in most projects Class based singletonHere we will implement singleton class that will always return the same instance instead of create a new one Due to the fact that constructor calls are always expected to return new objects by design this behavior cannot be implemented with a regular constructor But what if we return something from the constructor Let s take a look class Store someValue foo constructor return anotherValue bar const store new Store console log store someValue undefinedconsole log store anotherValue barAs we can see if we return an object from constructor that object will be returned as instance of the class Using this trick we can define and store an instance in a class field and return it in case if that value already exist class WebSocketService constructor if WebSocketService instance return WebSocketService instance WebSocketService instance this const socket new WebSocketService const socket new WebSocketService console log socket socket true Class based singleton with instance in function closureThe previous example is not the most correct and clean since the instance field remains available and we can override it manually Let s examine the most efficient way to implement a singleton The approach is to create a wrapper function from which we will return our class and in the closure of this function we will create our instance field const GlobalStore gt let instance null return class GlobalStore constructor if instance null instance this return instance In this example we put an instance in the function closure Then in the class constructor we check if we have an instance of the class and if not we assign a value to the instance and return it Also you can notice the wrapper function is created and immediately called thus we have created a closure inaccessible from the outside and the class can easily read and redefine values from the closure As a bonus of that approach is that you can add any variable or logic to the closure resulting you get real private methods which you won t be able to access from the instance	2022-10-10 06:44:09
海外TECH	DEV Community	Foal v2.11 has been released with better password management	https://dev.to/loicpoullain/foal-v211-has-been-released-with-better-password-management-4mbp	Foal v has been released with better password managementVersion of Foal is out Here are the improvements that it brings Number of Iterations on Password Hashing Has Been IncreasedThe PBKDF algorithm used for password hashing uses a number of iterations to hash passwords This work factor is deliberate and slows down potential attackers making attacks against hashed passwords more difficult As computing power increases the number of iterations must also increase This is why starting with version the number of iterations has been increased to To check that an existing password hash is using the latest recommended number of iterations you can use the passwordHashNeedsToBeRefreshed function The example below shows how to perform this check during a login and how to upgrade the password hash if the number of iterations turns out to be too low const email password ctx request body const user await User findOne email if user return new HttpResponseUnauthorized if await verifyPassword password user password return new HttpResponseUnauthorized highlight start This line must be after the password verification if passwordHashNeedsToBeRefreshed user password user password await hashPassword password await user save highlight end Log the user in	2022-10-10 06:24:27
ニュース	BBC News - Home	Ukraine war: BBC journalist ducks as explosions hit central Kyiv	https://www.bbc.co.uk/news/world-europe-63197951?at_medium=RSS&at_campaign=KARANGA	capital	2022-10-10 06:06:15
ニュース	BBC News - Home	Bank of England bolsters plan to calm market turmoil	https://www.bbc.co.uk/news/business-63198341?at_medium=RSS&at_campaign=KARANGA	final	2022-10-10 06:57:41
ニュース	BBC News - Home	Thai nursery: CNN apologises for entering site of deadly attack	https://www.bbc.co.uk/news/world-asia-63196932?at_medium=RSS&at_campaign=KARANGA	attackthe	2022-10-10 06:17:24