slikts

React context vs Redux in 2020

The [React docs][condoc] give some example use cases for context:

Context is designed to share data that can be considered “global” for a tree of React components, such as the current authenticated user, theme, or preferred language.

The common property of these use cases is that data like the current theme doesn't change often and needs to be shared deep down the component tree, which would be cumbersome with "[prop drilling][drill]". Something else that needs to be shared everywhere is the application state when using a "single source of truth" pattern, so it would follow that the context API would help with that as well, but there's a catch: components that use context will rerender every time that the provided value changes, so sharing the whole application state through context would cause excessive render lifecycles.

slikts

Appreciating the elegant simplicity of Immer

There is an ongoing shift in programming towards a more constrained mindset, recognizing shared mutable state and side effects as significant sources of accidental complexity and concepts like immutability and reactive, unidirectional pipelines as ways to overcome it. Simplicity is less optional than before, based on an understanding about the limited capacity of human working memory and based on programming language theory and practice. The functional programming ideas seeping into the mainstream leave less people to say that they wouldn't need them because of maybe never having used them.

The basic idea of controlling complexity through constraints is not novel at all, though, and it raises a valid question about why this shift has taken so long to develop, despite the overall trends towards automation and productivity. For example, the distincti

gricard

If you enjoyed reading this, I'm intending to do more blogging like this over here: https://cdgd.tech

This is not a complaint about Webpack or v4 in any way. This is just a record of my process trying it out so I could provide feedback to the webpack team

Hmm... I don't see any docs for 4.0 on https://webpack.js.org. I guess I'll just wing it. All I need to do is npm i -D webpack@next, right?

+ webpack@4.0.0-beta.2

posener

Story: Writing Scripts with Go

This is a story about how I tried to use Go for scripting. In this story, I’ll discuss the need for a Go script, how we would expect it to behave and the possible implementations; During the discussion I’ll deep dive to scripts, shells, and shebangs. Finally, we’ll discuss solutions that will make Go scripts work.

Why Go is good for scripting?

While python and bash are popular scripting languages, C, C++ and Java are not used for scripts at all, and some languages are somewhere in between.

zcaceres

'Include' in Sequelize: The One Confusing Query That You Should Memorize

When querying your database in Sequelize, you'll often want data associated with a particular model which isn't in the model's table directly. This data is usually typically associated through join tables (e.g. a 'hasMany' or 'belongsToMany' association), or a foreign key (e.g. a 'hasOne' or 'belongsTo' association).

When you query, you'll receive just the rows you've looked for. With eager loading, you'll also get any associated data. For some reason, I can never remember the proper way to do eager loading when writing my Sequelize queries. I've seen others struggle with the same thing.

Eager loading is confusing because the 'include' that is uses has unfamiliar fields is set in an array rather than just an object.

So let's go through the one query that's worth memorizing to handle your eager loading.

The Basic Query

bvaughn

React lifecycle cheatsheet

Method	Side effects1	State updates2	Example uses
Mounting
componentWillMount		✓	Constructor equivalent for createClass
render			Create and return element(s)
componentDidMount	✓	✓	DOM manipulations, network requests, etc.
Updating
componentWillReceiveProps		✓	Update state based on changed props

fernandohu

Reading data before application startup in Angular 2

In this demonstration I will show you how to read data in Angular2 final release before application startup. You can use it to read configuration files like you do in other languages like Java, Python, Ruby, Php.

This is how the demonstration will load data:

a) It will read an env file named 'env.json'. This file indicates what is the current working environment. Options are: 'production' and 'development';

b) It will read a config JSON file based on what is found in env file. If env is "production", the file is 'config.production.json'. If env is "development", the file is 'config.development.json'.

markerikson

[02:06 PM] acemarke: @Steven : a couple other thoughts on the whole NODE_ENV thing. First, per my comments, it really is a Node concept. It's a system environment variable that Node exposes to your application, and apparently the Express web server library popularized using its value to determine whether to do optimizations or not
[02:08 PM] acemarke: Second, because of its use within the Node ecosystem, web-focused libraries also started using it to determine whether to they were being run in a "development" environment vs a "production" environment, with corresponding optimizations. For example, React uses that as the equivalent of a C #ifdef to act as conditional checking for debug logging and perf tracking. If process.env.NODE_ENV is set to "production", all those if clauses will evaluate to false.
Third, in conjunction with a tool like UglifyJS that does minification and removal of dead code blocks, a clause that is surrounded with if(process.env.NODE_ENV !== "development")

armw4

The Beginning

Yes...it's true...redux is smart....smarter than you even know. It really does want to help you. It strives to be sane and easy to reason about. With that being said, redux gives you optimizations for free that you probably were completely unaware of.

connect()

connect is the most important thing in redux land IMO. This is where you tie the knot between redux and your underlying components. You usually take state and propogate it down your component hiearchy in the form of props. From there, presentational

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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