If you have dabbled in web development before, there is a high chance that you have worked with what's known as asynchronous operations. These are programmatic operations that don’t block the flow of execution, and allow users to continue using a website while the response is being fetched.

According to the Node.js docs, blocking "is when the execution of additional JavaScript in the Node.js process must wait until a non-JavaScript operation completes. This happens because the event loop is unable to continue running JavaScript while a blocking operation is occurring."

People have started hating on JavaScript because they don’t have a good understanding of these three concepts! But with our visual guide, you will be able to master these and start working with them today.