Code asynchrone avec JavaScript: Enchainement des promises en javascript

Bonjour les amis, dans cette nouvelle série de vidéo on va parler de code asynchrone avec JavaScript, et on sera focaliser sur la notion de Fetch, Promise, callback Function et Aync et Await

Dans cette vidéo il sera question de vous montrer comment est-ce que c’est possible de faire implémentation des plusieurs promises avec qu’une seule ligne de code

JavaScript Orienté Objet : http://bit.ly/JavaScriptOrienteObjet
Code source : https://github.com/drcmind/Code-asynchrone-JavaScript
Téléchargez VS Code : https://code.visualstudio.com/

#javascript #programming #web-development #developer

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Code asynchrone avec JavaScript: Enchainement des promises en javascript

Code asynchrone avec JavaScript: Enchainement des promises en javascript

Bonjour les amis, dans cette nouvelle série de vidéo on va parler de code asynchrone avec JavaScript, et on sera focaliser sur la notion de Fetch, Promise, callback Function et Aync et Await

Dans cette vidéo il sera question de vous montrer comment est-ce que c’est possible de faire implémentation des plusieurs promises avec qu’une seule ligne de code

JavaScript Orienté Objet : http://bit.ly/JavaScriptOrienteObjet
Code source : https://github.com/drcmind/Code-asynchrone-JavaScript
Téléchargez VS Code : https://code.visualstudio.com/

#javascript #programming #web-development #developer

A Beginner’s Guide To Promises In JavaScript

Welcome to my post about the JavaScript Promises. I hope it can be helpful since when we start programming it is difficult to enter the context.

Promises are one of the largest tools in the world of JavaScript that helps us to manage future situations in the flow of execution of a program.

The promises originated in the realm of functional programming, generally to handle asynchronous programming. In short, they allow us to define how data that will only be available in the future will be treated, specifying what will be done with that data later.

The promises were introduced in the standard in ES6, the truth is that they have been used for a long time since several libraries had implemented them to solve their needs in a more elegant way.

Image for post

The Promise object represents the eventual completion or failure of an asynchronous operation and its resulting value.

#programming #coding #javascript-promise #promises #javascript

Maud  Rosenbaum

Maud Rosenbaum

1600253460

JavaScript Asynchronous Operation — Read File Directory with Callback or Promises

Asynchronous Operation — Why do we care?

JavaScript is a synchronous, blocking, single threaded language. Synchronous single threaded means JavaScript waits for the task to be completed before being able to move on to the next task. However, Asynchronous JavaScript makes it so much faster if each task takes a really long time! Instead of waiting for the task beforehand to move on, there can be independent threads to start the tasks simultaneously.

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http://www.phpmind.com/blog/2017/05/synchronous-and-asynchronous/

In the computer programming world, synchronous and asynchronous may still be considered “fast” in human time. But let’s imagine a scenario if a request was sent to read an entire database of files and there are files in there are REALLY huge therefore take a long time to read. Instead of waiting, what if we can start reading the other files in the directory at the same time. This is Asynchronous JavaScript.

Asynchronous Operation — Code Styles

In JavaScript, functions are first class citizens. This means functions can be treated like values of other types. Functions can be passed to other functions as arguments, returned from other functions as values, and stored in variables.

Async operations are put into an event queue which runs after the main thread has finished processing so that they do not stop subsequent JavaScript from running.

There are 2 main asynchronous concepts that JavaScript uses which leverage functions first class citizenship:

  1. Async Callbacks
  2. Promises

For other examples, to help you further solidify your understanding of these 2 concepts.

Introducing asynchronous JavaScript

In this article we briefly recap the problems associated with synchronous JavaScript, and take a first look at some of…

developer.mozilla.org

Callbacks, Promises, and Async

Synchronous operations in JavaScript entails having each step of an operation waits for the previous step to execute…

scotch.io

Let’s consider an AJAX (Asynchronous JavaScript and XML) request to the server.

Image for post

http://www.phpmind.com/blog/2017/05/synchronous-and-asynchronous/

The user clicks on the browser which results in sending an HTTP request to the server to read an entire directory, which could take some time. Instead of having the browser stop running any other functions and wait for the response, another function is set up to wait for this response and react when the response is received.

Let’s see how we can write these Asynchronous Operations.

#programming #javascript #asynchronous #promises #coding

Rahul Jangid

1622207074

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

  • For single line comment in JavaScript we have to use // (double slashes)
  • For multiple line comments we have to use / * – – * /
<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Julie  Donnelly

Julie Donnelly

1602406920

JavaScript Promise: Methods Comparison

Introduction

Promises in JavaScript are used to handle asynchronous operations by keeping track of whether a certain event has happened. If that certain event has taken place, it determines what happens next. Promises return a value which is either a resolved value or a reason why it’s rejected. They can handle multiple asynchronous operations easily and they provide better error handling than callbacks and events.

Callback: A callback is a function that is passed into another function as an argument to be executed later.

Events: Events provide a dynamic interface to a WebPage and are connected to elements in the Document Object Model(DOM), for example: onclick(), onmouseover() etc.

A Promise has four states

Pending: Before the event has happened, the promise is in the pending state.

Settled: Once the event has happened it is then in the settled state.

Fulfilled: Action related to the promise has succeeded.

Rejected: Action related to the promise has failed.

#javascript #javascript-development #javascript-tutorial #promises #javascript-tips