Utilizing setInterval() for straightforward and continuous polling operations

Question

Utilizing setInterval() for straightforward and continuous polling operations

When developing a basic web application that requires periodic data updates for the user, is there any disadvantage to using setInterval() to fetch JSON from an endpoint instead of utilizing a more formal polling framework?

As an illustration, let's consider the scenario where I need to refresh the status of a processing job every 5 seconds.

javascript ajax setinterval polling

Answer 1

Answer №1

To prevent any potential delays or function stacking, I recommend using the setTimeout method. This allows you to schedule a function to run after a specified delay and ensure that each request is handled efficiently.

Here's an example implementation:

function updateData() {
    // Perform Ajax call here, and then schedule a refresh:
    setTimeout(updateData, 5000);
    // Additional logic...
}

// Initial trigger for the function, or directly call updateData
setTimeout(updateData, 5000);

Answer 2

To prevent any potential delays or function stacking, I recommend using the setTimeout method. This allows you to schedule a function to run after a specified delay and ensure that each request is handled efficiently.

Here's an example implementation:

function updateData() {
    // Perform Ajax call here, and then schedule a refresh:
    setTimeout(updateData, 5000);
    // Additional logic...
}

// Initial trigger for the function, or directly call updateData
setTimeout(updateData, 5000);

Answer 3

Answer №2

Implementing a basic non-blocking polling function in modern browsers can be achieved using Promises:

var wait = time => new Promise(resolve => setTimeout(resolve, time))
var pollFunction = (promiseFunc, time) => promiseFunc().then(
             wait(time).then(() => pollFunction(promiseFunc, time)))

// Print "Hello World!" every second
pollFunction(() => new Promise(() => console.log('Hello World!')), 1000)

Answer 4

Implementing a basic non-blocking polling function in modern browsers can be achieved using Promises:

var wait = time => new Promise(resolve => setTimeout(resolve, time))
var pollFunction = (promiseFunc, time) => promiseFunc().then(
             wait(time).then(() => pollFunction(promiseFunc, time)))

// Print "Hello World!" every second
pollFunction(() => new Promise(() => console.log('Hello World!')), 1000)

Answer 5

Answer №3

Here is a simple way to achieve this:

let count = 0, limit = 50, speed = 100;

function iterate(){
    count += 1; 
    /* Your code goes here. Blah blah... */
    if (count === limit) clearInterval(timer);
}

let timer = setInterval(iterate, speed);

Answer 6

Here is a simple way to achieve this:

let count = 0, limit = 50, speed = 100;

function iterate(){
    count += 1; 
    /* Your code goes here. Blah blah... */
    if (count === limit) clearInterval(timer);
}

let timer = setInterval(iterate, speed);

Answer 7

Answer №4

Although this question is from a while back, I came across it and wanted to share some alternative solutions to enhance it in the StackOverflow fashion. One approach you might want to consider is similar to the method described here, known as long polling. Another option is to use WebSockets, such as socket.io.

The first method involves sending a single AJAX request and waiting for a response before sending another one. On the backend, the response is only delivered once the status changes, allowing you to continuously monitor the status until it changes.

On the other hand, socket.io acts like jQuery for Websockets, enabling you to establish a socket connection with any browser to push real-time data without needing to constantly poll the server. This system is akin to Blackberry's instant notifications and is ideal for achieving immediate updates.

Answer 8

Although this question is from a while back, I came across it and wanted to share some alternative solutions to enhance it in the StackOverflow fashion. One approach you might want to consider is similar to the method described here, known as long polling. Another option is to use WebSockets, such as socket.io.

The first method involves sending a single AJAX request and waiting for a response before sending another one. On the backend, the response is only delivered once the status changes, allowing you to continuously monitor the status until it changes.

On the other hand, socket.io acts like jQuery for Websockets, enabling you to establish a socket connection with any browser to push real-time data without needing to constantly poll the server. This system is akin to Blackberry's instant notifications and is ideal for achieving immediate updates.

Answer 9

Answer №5

Make adjustments to @bschlueter's response, and remember, you have the ability to terminate this polling function by executing cancelCallback()

let cancelCallback = () => {};

var sleep = (interval) => {
  return new Promise((resolve) => {
    cancelCallback = () => {
      console.log("Canceling...");
      // send cancellation message...
      return resolve('Canceled');
    }
    setTimeout(() => {
      resolve("tick");
    }, interval)
  })
}

var poll = (promiseFunction, interval, timeout) => promiseFunction().then(() => {
  let snooze = async(interval) => {
    let result = await sleep(interval);
    // perform actions once sleep is completed
    console.log("Sleep has ended, do something...");
    return result;
  }


  // check if cancelCallback is an empty function,
  // if so, schedule a timeout to trigger cancelCallback()
  if (cancelCallback.toString() === "() => {}") {
    console.log("Setting timeout to execute cancelCallback()")
    setTimeout(() => {
      cancelCallback()
    }, timeout);
  }

  snooze(interval).then((result) => {
    // verify if sleep was canceled, if not, proceed with polling
    if (result !== 'Canceled') {
      poll(promiseFunction, interval);
    } else {
      console.log(result);
    }
  })

  // perform action1...
  console.log("Performing action1...");

})


poll(() => new Promise((resolve) => {
  console.log('Hello World!');
  resolve(); 
}), 3000, 10000);

// perform action2...
console.log("Performing action2....")

Answer 10

Make adjustments to @bschlueter's response, and remember, you have the ability to terminate this polling function by executing cancelCallback()

let cancelCallback = () => {};

var sleep = (interval) => {
  return new Promise((resolve) => {
    cancelCallback = () => {
      console.log("Canceling...");
      // send cancellation message...
      return resolve('Canceled');
    }
    setTimeout(() => {
      resolve("tick");
    }, interval)
  })
}

var poll = (promiseFunction, interval, timeout) => promiseFunction().then(() => {
  let snooze = async(interval) => {
    let result = await sleep(interval);
    // perform actions once sleep is completed
    console.log("Sleep has ended, do something...");
    return result;
  }


  // check if cancelCallback is an empty function,
  // if so, schedule a timeout to trigger cancelCallback()
  if (cancelCallback.toString() === "() => {}") {
    console.log("Setting timeout to execute cancelCallback()")
    setTimeout(() => {
      cancelCallback()
    }, timeout);
  }

  snooze(interval).then((result) => {
    // verify if sleep was canceled, if not, proceed with polling
    if (result !== 'Canceled') {
      poll(promiseFunction, interval);
    } else {
      console.log(result);
    }
  })

  // perform action1...
  console.log("Performing action1...");

})


poll(() => new Promise((resolve) => {
  console.log('Hello World!');
  resolve(); 
}), 3000, 10000);

// perform action2...
console.log("Performing action2....")

Utilizing setInterval() for straightforward and continuous polling operations

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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