The main thread of node executes js code. When it is an asynchronous operation, node will hand it over to libuv for execution, and then execute the code behind the asynchronous operation. After libuv is executed, it will be placed in a circular queue. libuv will have an event loop (Event Loop) similar to while(true). This event loop exists in the single thread of the node (that is, the main thread). The main thread loops Get the event execution callback function.
So what is the process of the main thread looping to retrieve events and executing the asynchronous code behind it? It is impossible for a thread to do two things at the same time. After executing the asynchronous code, will the CPU loop to fetch events when it is idle?