A Named Promise Task
Inspire from https://stackoverflow.com/a/53540586/314173
No Queue, Just a simple promise mechanics to help you run serial tasks.
When you need a Javascript task manager, but no want callback like async.queue
This package support named tasks, Please read example.js.
Install
npm install --save named-promise-task
Need platform supoort Promise.finally
Usage
Method
addTask: Add a named task with parameters
Properties
size: the running task numbers
isRunning: true/false of having running task
Events
start: one or more tasks is running
stop: all task completed
Promise methods
then: the task's result
catch: an exception from task
Examples
const PromiseTask = require('named-promise-task')
const sleep = ( ms ) => new Promise( ( resolve, _ ) => setTimeout( () => resolve(), ms ) )
const that = 'outer'
const fetch = async ( p1 ) => {
await sleep( 1000 )
console.log( 'fetch', p1, this, that )
return 'fetch result'
}
async function fetch2 ( p1, p2 ) {
await sleep( 1000 )
//"this" is context
console.log( 'fetch2', p1, p2 )
}
const error = async ( ...values ) => {
await sleep( 1000 )
throw 'error'
}
async function test () {
const that = 'inner'
const upload = async ( p1, p2, p3 ) => {
await sleep( 1000 )
console.log( 'upload', p1, p2, p3 )
}
const manager = new PromiseTask( this, {
fetch: fetch,
fetch2: fetch2,
upload: upload,
error: error
} )
manager.on('start', () =>{
console.log('start')
})
manager.on('stop', () =>{
console.log('stop')
})
manager.addTask( 'fetch', 1 ).then( console.log )
manager.addTask( 'fetch2', 2, "str" )
manager.addTask( 'error', 3, "str", { options: 3 } ).then( console.log ).catch( console.error )
manager.addTask( 'upload', 4, "str", { options: 4 } )
await sleep( 1000 )
manager.addTask( 'fetch', 5, "str", { options: 5 } )
}
test()