I am a huge fan of Udemy when it comes to learning. They have programming courses for almost anything. I have put together a selection of the courses I have used as well as a few from the popular developer Wes Bos who has his own platform and is not on Udemy. These courses cover Javascript, React, Redux, MERN, TDD/BDD and much more! Even Data Structures and Algorithms is covered so you can get yourself ready for interviews too!

TDD/BDD

Use Jest and React Testing Framework/Enzyme for testing frontend code. And use Mocha and Chai for testing backend code.

Javascript

The Complete JavaScript Course 2020: Build Real Projects!
Modern JavaScript From The Beginning
20 Web Projects With Vanilla JavaScript
Beginner Javascript

React and Redux

React - The Complete Guide (incl Hooks, React Router, Redux) (TDD/BDD Modules)
Modern React with Redux [2020 Update]
Advanced React and Redux (TDD/BDD Modules)
Complete React Developer in 2020 (w/ Redux, Hooks, GraphQL) (TDD/BDD Modules)
The Complete Junior to Senior Web Developer Roadmap (2020) (TDD/BDD Modules)

MERN Stack

MERN Stack Front To Back: Full Stack React, Redux & Node.js
Node with React: Fullstack Web Development
React Front To Back
Advanced React and Redux (TDD/BDD Modules)
Advanced React (TDD/BDD Modules)

Node, Deno, MongoDB and SQL

NodeJS - The Complete Guide (MVC, REST APIs, GraphQL, Deno)

Data Structures and Algorithms

The Coding Interview Bootcamp: Algorithms + Data Structures
Master the Coding Interview: Data Structures + Algorithms
JavaScript Algorithms and Data Structures Masterclass