Gain insights into JavaScript from basics to ES2021, delve into TypeScript essentials, and test your knowledge through quizzes and coding challenges to reinforce learning.

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node:latest

Jan/2021 Updated to include ES2021

Whether you are a complete beginner or you have some knowledge of JavaScript, this course will guide you from the basics of the language to all the new features introduced up until 2021.  You’ll test your knowledge with quizzes and some coding challenges at the end of each chapter. 

After following this course, the functions and variables let, const, generators, promises and async won't be a problem anymore.

If you want to experience something new, this course also includes an introduction to the basics of TypeScript, which is a must-know for any JavaScript developer.

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Just completed this amazing ebook  by @montalesi. I would recommend anyone who is looking to upgrade their es6, 7 or 8 knowledge to go through the book once. It is short crisp and to the point and serves as a great resource that you can go through in limited time

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I have been working as a front-end developer for over 5 years but I am still reading the book by @montalesi because I find it really exhaustive and well written.

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The Complete Guide to Modern JavaScript

# What's new in ES2021

Let's get started with the first of the new ES2021 features:

# String.prototype.replaceAll

`String.replace` is a useful method that allows us to replace a pattern in a string with something else. The problem is that if we want to use a `string` as a pattern and not a RegEx, only the **first** occurrence will get replaced.

const str = "I like my dog, my dog loves me";
const newStr = str.replace("dog", "cat");
console.log(newStr);
// "I like my cat, my dog loves me"


As the name implies, `String.replaceAll` will do exactly what we need in this scenario, replace all the matching pattern, allowing us to easily replace all mentions of a substring, without the use of RegEx:

const str = "I like my dog, my dog loves me";
const newStr = str.replaceAll("dog", "cat");
console.log(newStr);
// "I like my cat, my cat loves me"


[Read More](https://github.com/tc39/proposal-string-replaceall)

&nbsp;

# Promise.any

During the past years we've seen new methods such as `Promise.all` and `Promise.race` with ES6, `Promise.allSettled` last year with ES2020 and ES2021 will introduce a new one: `Promise.any`.

I bet you can already tell what it does from the name of the method.

`Promise.any` shorts-circuits once a given promise is fulfilled but will continue until all promises are rejected.

Don't get confused with `Promise.race` because with `race`, the promise short-circuits once one of the given promises resolves **or rejects**.

They have similar behavior for what concerns fulfillment but very different for rejection.

If all the promises inside of `Promise.any` fails, it will throw an `AggregateError` (a subclass of `Error`) containing the rejection reasons of all the promises.

We can use it like this:

Introduction

Intro To JavaScript

ES6

From ES2016 to ES2022

Intro To TypeScript

Appendix

What's new in ES2021

What’s new in ES2021

String.prototype.replaceAll

Promise.any