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JavaScript Timers and Asynchronous Code

JavaScript Timers and Asynchronous Code refer to the process of executing code at a later time or in a non-blocking manner. JavaScript provides several methods for scheduling code to run at a later time, including setTimeout, setInterval, and requestAnimationFrame.

Here is an example of using the setTimeout method in JavaScript:

setTimeout(function() {
  console.log("Hello World");
}, 1000);

In the example, the setTimeout method is used to execute a function that logs "Hello World" to the console after 1000 milliseconds (1 second).

Here is another example of using the setInterval method in JavaScript:

let counter = 0;
setInterval(function() {
  console.log("Hello World: " + ++counter);
}, 1000);

In the example, the setInterval method is used to execute a function that logs "Hello World: n" to the console every 1000 milliseconds (1 second), where n is the current value of the counter variable. The counter variable is incremented every time the function is executed.

Asynchronous code is code that runs in the background without blocking the rest of the code from executing. JavaScript is a single-threaded language, which means that only one piece of code can be executed at a time. However, JavaScript provides several methods for executing code asynchronously, including setTimeout, setInterval, requestAnimationFrame, and promises.

Here is an example of using promises in JavaScript:

let promise = new Promise(function(resolve, reject) {
  setTimeout(function() {
    resolve("Hello World");
  }, 1000);
});

promise.then(function(result) {
  console.log(result);
});

In the example, a promise is created that resolves with the value "Hello World" after 1000 milliseconds (1 second). The then method is used to execute a function that logs the result to the console when the promise is resolved.

JavaScript Timers and Asynchronous Code are important concepts in JavaScript programming and web development, as they allow you to schedule code to run at a later time or in a non-blocking manner, and provide a way to execute code asynchronously. Understanding how to use JavaScript timers and how to work with asynchronous code is an important part of JavaScript programming and web development.



Next: JavaScript Objects

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