On macro task and micro task;
Definition: tasks initiated by the host (browser) can be called macrotasks; The engine (JS) itself can also initiate a task, which is called a microtask.
Js is basically a single-threaded language, and the first thing to do is to execute a synchronous queue, which you can only put aside for asynchronous operations. Synchronization won’t be discussed too much.
So those that initiate are macro and those that initiate are micro;
Macro task
Script, setTimeout, setInterval, I/O, UI interaction events, postMessage, MessageChannel, setImmediate(node.js environment);
The micro tasks
promise async await
Therefore, the overall execution sequence is:
Synchronous Task > Micro Task > Macro Task
Take the following example
The first is the synchronization queue log(4) ==>async1==> Async2 ==> Promise ==>log8
Micro task log(2)==>log(7)
Macro task setTimeout
So the output result 41368275==
Ali rookie interview yesterday, received rejection mail today, before still can insist on two or three rounds, hit. That’s probably the problem. I feel like I didn’t answer that well. Better late than never. Hope the latecomers meet play well.
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