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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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.

@SuperCoder4

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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@battago

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 is a Proxy?

From MDN:

> The **Proxy** object is used to define custom behavior for fundamental operations (e.g. property lookup, assignment, enumeration, function invocation, etc).

&nbsp;

# How to use a `Proxy` ?

This is how we create a Proxy:


- our `target` can be anything, from an object, to a function, to another `Proxy`
- a `handler` is an object which will define the behavior of our `Proxy` when an operation is performed on it


// our object
const dog = { breed: "German Shephard", age: 5}

// our Proxy
const dogProxy = new Proxy(dog, {
  get(target,breed){
    return target[breed].toUpperCase();
  },
  set(target, breed, value){
    console.log("changing breed to...");
    target[breed] = value;
  }
});

console.log(dogProxy.breed);
// "GERMAN SHEPHARD"
console.log(dogProxy.breed = "Labrador")
// changing breed to...
// "Labrador"
console.log(dogProxy.breed);
// "LABRADOR"


When we call the `get` method, we step inside the normal flow and change the value of the breed to uppercase.

When setting a new value, we step in again and log a short message before setting the value.

Proxies can be very useful. For example, we can use them to validate data.

Learn how to define custom behaviors for fundamental operations with Proxies.

Introduction

Intro To JavaScript

ES6

From ES2016 to ES2022

Intro To TypeScript

Appendix

Proxies

What is a Proxy? #

How to use a `Proxy` ? #

Proxies

What is a Proxy? #

How to use a Proxy ? #

How to use a `Proxy` ? #