Running Concurrent Requests With Async/Await and Promise.all

In this article, I’d like to touch on async, await, and Promise.all in JavaScript. First, I’ll talk about concurrency vs. parallelism and why we will be targeting parallelism in this article. Then, I’ll talk about how to use async and await to implement a parallel algorithm in serial and how to make it work in parallel by using Promise.all. Finally, I’ll create an example project using Salesforce’s Lightning Web Components where I will build an art gallery using Harvard’s Art Gallery API.

Concurrency vs. Parallelism

I want to quickly touch on the difference between concurrency and parallelism. You can relate concurrency to how a single-threaded CPU processes multiple tasks. Single-threaded CPUs emulate parallelism by switching between processes quickly enough that it seems like multiple things are happening at the same time. Parallelism is when a CPU has multiple cores and can actually run two tasks at the exact same time. Another great example is this:

Concurrency is two lines of customers ordering from a single cashier (lines take turns ordering); Parallelism is two lines of customers ordering from two cashiers (each line gets its own cashier). [1]

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Understanding JavaScript: Promises, Async & Await!!

Analogy

We all know the importance of promises in our life. We even have a special day dedicated to it :) But how well do we know the importance of promises in JavaScript? Well if you don’t know it yet, it’s a great time to know it because they are becoming more and more popular. So what are promises? Let’s try to understand it through an analogy.

Suppose you are a top class rapper and you haven’t released an album for a while and fans are asking for it day and night. So what you do is that you “promise” them that whenever it will be out, all of them would be notified. To get this done you give your fans a list. They can fill in their email addresses, so that when the album becomes available, all the subscribers instantly receive it. And even if something goes wrong, say a pandemic, so that you can’t release the album, they will still be notified.

Now everyone is happy: You, because the people don’t crowd you anymore, and fans, because they won’t miss any news on the album.

This is a real-life analogy for things we often have in programming:

1. A “producing code” that does something and may take time. That’s a “rapper”.
2. A “consuming code” that wants the result of the “producing code” once it’s ready. Many functions may need that result. These are the “fans”.
3. A promise is a special JavaScript object that links the “producing code” and the “consuming code” together. In terms of our analogy: this is the “subscription list”. The “producing code” takes whatever time it needs to produce the promised result, and the “promise” makes that result available to all of the subscribed code when it’s ready.

JavaScript promises are much more complex than a simple subscription list: they have additional features and limitations. But it’s fine to begin with.

#async #promises #javascript #development #await

React Async Await Fetch Api Call Example

https://www.codecheef.org/article/react-async-await-fetch-api-call-example

#react #fetch-api #async #await #async-await

6 Things About HTTP Request in Dart For Beginners

Introduction

If you are here and a beginner, that means you want to learn everything about making an API request using Dart in Flutter, then you are in the right place for the HTTP tutorial. So without wasting any time, let’s start with this flutter tutorial. We will cover the essential topics required to work with the HTTP request in Dart.

What is Rest API in Dart ?

Rest APIs are a way to fetch data from the internet in flutter or communicate the server from the app and get some essential information from your server to the app. This information can be regarding your app’s data, user’s data, or any data you want to share globally from your app to all of your users.

This HTTP request fetches in a unique JSON format, and then the information is fetched from the JSON and put in the UI of the app.

Every programming language has a way of some internet connectivity i.e, use this rest API developed on the server and fetch data from the internet. To use this request feature, we have to add HTTP package in flutter, add this flutter package add in your project to use the http feature. Add this HTTP package to your pubspec.yaml, and run a command in terminal :

flutter packages get

#dart #flutter #async await #async function #cancel http api request in flutter #fetch data from the internet #flutter cancel future #flutter get request example #flutter post request example #future of flutter #http tutorial

What is promise and Async/Await?

Base on developer requirement we are going to cover promises and async/await with this article. Some developers are still confused about how to use promises and async javascript. JavaScript Promises are very similar to real-life promises made by us. After that promises, we make a plan and assure that we are successfully have done or broke.

JS promises are completion or failure.

#async #await #javascript #js

Async, Await, and Promises in Express for Node.js

Here’s how you can easily work with async/await and Promises in express, right now!
@root/async-router: https://github.com/therootcompany/async-router
Express 5.0 promised native support for async/await and Promises - and it even delivered, but then was never officially published. It’s still stuck in alpha.
There are many 3rd party modules that add promise support to express, but most of them are just plain terrible.
Thankfully I express-promisify-router, which behaves exactly as any sane, rational person who has used express would expect it to behave. That said, since it doesn’t seem to be actively maintained, I added the ability to use error handler functions and republished it as @root/async-router.

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#node.js #node #webdevelopment #webdeveloper #async #await