How can I implement a loop using .then in JavaScript?

Question

How can I implement a loop using .then in JavaScript?

Looking to understand the .then concept in JavaScript, I am curious if it is feasible to generate a series of .then's using a for loop.

request.send(myRequest)
    .then(r => console.log(r, 0))
    .then(r => console.log(r, 1))
    .then(r => console.log(r, 2))
    .then(r => console.log(r, 3))
    .then(r => console.log(r, 4))

Instead of manually adding each .then, I am interested in dynamically creating a chain of .then's so that I can execute .then an incremental number of times using i++.

Indeed, it is possible.

javascript asynchronous

Answer 1

Answer №1

When promises do not have dependencies, you can utilize the `promise.all([promise1,promise2]).then((arrayofresult)=>{})` method.

Alternatively, you can explore using an external library called bluebird.

For more information, check out this link: http://bluebirdjs.com/docs/api/promise.map.html

Answer 2

When promises do not have dependencies, you can utilize the `promise.all([promise1,promise2]).then((arrayofresult)=>{})` method.

Alternatively, you can explore using an external library called bluebird.

For more information, check out this link: http://bluebirdjs.com/docs/api/promise.map.html

Answer 3

Answer №2

If you need to execute tasks in a sequential manner, one approach is as follows:

async function handleSequentialTasks(response, index, maxIndex) {
  if(index < maxIndex) {
     await performAsyncTask();

     return handleSequentialTasks(response, index+1, maxIndex)
  }
}

request.send(myRequest)
.then(response => {
   return handleSequentialTasks(response, index, 10)
})

However, the best way to tackle this problem can vary based on the specific scenario.

Answer 4

If you need to execute tasks in a sequential manner, one approach is as follows:

async function handleSequentialTasks(response, index, maxIndex) {
  if(index < maxIndex) {
     await performAsyncTask();

     return handleSequentialTasks(response, index+1, maxIndex)
  }
}

request.send(myRequest)
.then(response => {
   return handleSequentialTasks(response, index, 10)
})

However, the best way to tackle this problem can vary based on the specific scenario.

Answer 5

Answer №3

If I'm not mistaken, it seems like you're interested in a more dynamic approach to creating promise chains. Here's a basic example that demonstrates how this can be achieved. You can customize and adjust it to suit your specific requirements.

function fetchData(info){
   return new Promise((resolve, reject) => resolve(info))
}

var dataArr = [5, 6, 7, 8]

dataArr.reduce((initData, item, indx) => initData.then(result => {
       console.log(result);
       return fetchData(item)
}), Promise.resolve(0)).then(dataResult => console.log(dataResult))

Answer 6

If I'm not mistaken, it seems like you're interested in a more dynamic approach to creating promise chains. Here's a basic example that demonstrates how this can be achieved. You can customize and adjust it to suit your specific requirements.

function fetchData(info){
   return new Promise((resolve, reject) => resolve(info))
}

var dataArr = [5, 6, 7, 8]

dataArr.reduce((initData, item, indx) => initData.then(result => {
       console.log(result);
       return fetchData(item)
}), Promise.resolve(0)).then(dataResult => console.log(dataResult))

How can I implement a loop using .then in JavaScript?

Answer №1

Answer №2

Answer №3

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