p-q-like
Q-like module for performing the most commonly used asynchronous operations with zero-dependency.
Installation
using npm:
npm install p-q-likeusing yarn:
yarn add p-q-likeUsage
// CommonJS `require`
const P = require('p-q-like')
// ECMAScript `import`
import P from 'p-q-like'Deferred promise
// Promised function without nesting
function someAsyncFunctionExample1() {
const deferred = P.defer()
setTimeout(() => {
deferred.resolve()
}, 1000)
return deferred.promise
}// One more example
const someAsyncFunctionExample2 = async () => {
const { promise, resolve } = P.defer()
await P.delay(1000)
resolve()
return promise
}Delay in the synchronous execution style
// Thenable delay in milliseconds
P.delay(1000).then(() => {
console.log('Delayed function executed after 1 second!')
})
// IIFE async await
(async () => {
await P.delay(1000)
})()Async operation on each item in an array
const array = [1, 2, 3]
// Supports concurrency modes
const concurrency = 1 // || 0: in parallel || 2+: in parallel with concurrency
const iterateEachOther = (value, index) => {
const deferred = P.defer()
setTimeout(() => {
console.log(`Item at index ${index}: ${value}`)
deferred.resolve()
}, 1000)
return deferred.promise
}
(async () => {
const { results, errors } = await P.forEach(array, iterateEachOther, concurrency)
if (!errors.length) console.log('All operations completed!')
})()API Reference
defer()
Returns a deferred promise that can be resolved or rejected later.
const someAsync = async () => {
const deferred = P.defer()
await someOtherAsync()
deferred.resolve()
return deferred.promise
}delay(timeout)
Returns a promise that resolves after a specified amount of time.
// pause for 1 second
await P.delay(1000)forEach(array, iterator, concurrency = 1)
Performs an async operation on each item in an array, with optional concurrency mode.
Returns a promise that resolves with the results and errors of the operations.
P.forEach(['zero', 'one', 'two'], (value, index) => {
return new Promise((resolve, reject) => {
setTimeout(() => {
console.log(`Item at index ${index}: ${value}`)
resolve()
}, 1000)
})
}).then(({ results, errors }) => {
console.log('All operations completed!')
})
// => Result
// Item at index 0: zero
// ...one second later...
// Item at index 1: one
// ...one second later...
// Item at index 2: two
// ...one second later...
// All operations completed!Concurrency modes
0
execute in parallel (Promise.all)
1
(default) execute one by one
2
execute in parallel with concurrency mode
License
MIT