You can first go through below videos to get a good understanding about JavaScript, but I will suggest to read 'Rediscovering JavaScript_ Master ES6, ES7, and ES8 ( PDFDrive.com )' by Venkat Subramaniam. And if you have watched his lectures & appreciate his way of explanation then you will also like this book & surely you will be adding a few hidden feathers which will be helping you to fly higher in the sky of JavaScript.