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ATUL WAMAN NAGOSE
ATUL WAMAN NAGOSE

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JavaScript Event Loop

Interviewer: You have 2 minutes. Explain the JavaScript Event Loop to me.
My answer: Challenge accepted, letโ€™s go! ๐Ÿš€

๐Ÿ”ธ Single-Threaded Execution:
JavaScript operates on a single-threaded model, meaning it can handle only one task at a time. The tasks are managed using the call stack, which executes functions one by one.

๐Ÿ”ธ Call Stack:
Imagine the call stack as a stack of plates. Each time a function is called, a plate is added to the stack. Once the function completes, the plate is removed.

๐Ÿ”ธ Web APIs:
For tasks like setTimeout, DOM events, or HTTP requests, JavaScript uses Web APIs provided by the browser. These tasks are processed outside the call stack.

๐Ÿ”ธ Callback Queue:
Once an asynchronous task finishes, its callback moves to the callback queue. The event loop only pushes the callback to the stack once the stack is empty.

๐Ÿ”ธ Event Loop:
The event loop acts as a gatekeeper, checking if the call stack is empty. When it is, it takes the first task from the callback queue and pushes it onto the stack.

๐Ÿ”ธ Microtasks Queue:
In addition to the callback queue, thereโ€™s a microtasks queue for tasks like promises. Microtasks are processed before any other callbacks, giving them higher priority.

๐Ÿ”ธ Priority Handling:
To summarize, the event loop checks the microtasks queue first, then moves on to the callback queue. This ensures critical tasks (e.g., promises) are executed before other callbacks.

And thatโ€™s the JavaScript Event Loop! ๐Ÿ”„

๐Ÿ’ก Stay curious, keep learning, and keep sharing! ๐Ÿ’ปโœจ

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