JavaScript Brain Teasers: Exercise Your Mind/

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Discussion: Waiting in Line

Discussion: Waiting in Line

Execute the code to understand the output and gain insights into the event loop and how JavaScript handles asynchronous tasks.

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Verifying the output

Now, it’s time to execute the code and observe the output.

Javascript (babel-node-es2024)
console.log("Start");
setTimeout(() => {
  console.log("Timeout");
}, 0);
Promise.resolve().then(() => {
  console.log("Promise");
});
console.log("End");

Understanding the output

Here, we have a mixture of synchronous and asynchronous operations and use console.log() to output different messages at various points in the code. Since the setTimeout() is set to 0 milliseconds, you might expect the messages to appear in the order of “Start,” “Timeout,” “Promise,” and “End.” However, the actual output is different because of the event loop and how JavaScript ...