queue-of-promises
Queue of promises. All promises are executed concurrently as they are added to the input queue. Regardless of which promise resolved earlier, output queue will always keep the order it was executed
To abort queue of promises please checkout abort-promise-queue
Zero-dependency, total size: 1755 B uncompressed and 1002 B gzip-compressed
Output queue returns an object { config, data, error }
- On successful response,
datawill contain the response body. - On error response,
errorwill contain the error message.
Install
npm install --save @nasimhuq/queue-of-promises
Typical usage
Require as CJS
const queueOfPromises = require('@nasimhuq/queue-of-promises');Import as ES6 Module
import queueOfPromises from '@nasimhuq/queue-of-promises';Examples
Example 1: Single batch of requests
import queueOfPromises from '@nasimhuq/queue-of-promises'
const api = (config) => {
return new Promise((resolve, reject) => {
const { output } = config
setTimeout(() => {
if (output.reject) {
reject(output)
} else {
resolve(output)
}
}, output.duration)
})
}
const multi = 1000
const reqConfigList = [
{
output: {
key: 'First',
duration: 1000 + multi,
},
},
{
output: {
key: 'Second',
duration: 500 + multi,
},
},
{
output: {
key: 'Third',
duration: 1300,
reject: true,
},
},
{
output: {
key: 'Fourth',
duration: 1300 + multi * 2,
reject: true,
},
},
{
output: {
key: 'Fifth',
duration: 1000 + multi * 3,
reject: true,
},
},
{
output: {
key: 'Sixth',
duration: 900 + multi,
},
},
{
output: {
key: 'Seventh',
duration: 700 + multi,
},
},
]
const test_single_batch = async (resolve) => {
const { inputQueue, outputQueue } = queueOfPromises(api)
reqConfigList.forEach((config) => {
inputQueue.next(config)
})
const start = Date.now()
try {
for await (const res of outputQueue) {
console.log(res)
const end = Date.now()
console.log('duration: ', end - start)
}
} catch (e) {
console.log('something went wrong!')
}
console.log('finished')
resolve() // this resolve is used for display purpose only
}
const test_multiple_batches = async (resolve) => {
const { inputQueue, outputQueue, closeQueue } = queueOfPromises(api, true, 500)
inputQueue.next(reqConfigList[0])
inputQueue.next(reqConfigList[1])
inputQueue.next(reqConfigList[2])
const start = Date.now()
setTimeout(() => {
console.log('new Batch:', Date.now() - start)
inputQueue.next(reqConfigList[3])
inputQueue.next(reqConfigList[4])
inputQueue.next(reqConfigList[5])
inputQueue.next(reqConfigList[6])
}, 3000)
setTimeout(() => {
closeQueue() // no more adding new fetch config to inputQueue after this call.
}, 5000)
try {
for await (const res of outputQueue) {
console.log(res)
const end = Date.now()
console.log('duration: ', end - start)
}
} catch (e) {
console.log('something went wrong!')
}
console.log('finished')
resolve() // this resolve is used for display purpose only
}
const test_multiple_batches_promise = async () => {
return new Promise(async (resolve) => {
test_multiple_batches(resolve);
})
}
const test_single_batch_promise = async () => {
return new Promise(async (resolve) => {
test_single_batch(resolve)
})
}
const allTests = async () => {
console.log('---------------------- single batch -------------------------')
await test_single_batch_promise()
console.log('------------------------multiple batches ------------------')
await test_multiple_batches_promise()
}
allTests()