Simple Async Task Queue

task_queue.js

function task1() {

    return new Promise((resolve) =>{
        setTimeout(() => {
            console.log('doing some work on state 1') 
            resolve({completed: true, value: 1})
        }, 50)
    }) 
}


/*
 *  This function will fail two times, demonstrating how our task runner can handle failure and re-entry. 
 */
const task2 = function() {
    let counter = 0

    return () => new Promise(function (resolve) {
        setTimeout(() => {
            let completed = false
            counter = counter + 1
            console.log('doing some work on state 2, success: ', counter===3, counter) 

            if(counter === 3) {
                completed = true 
            }
            resolve({completed, value: 2, message:'great!!'})
        }, 2000)
    }) 
}()

function task3() {

    return new Promise((resolve) =>{
        setTimeout(() => {
            console.log('doing some work on state 3') 
            resolve({completed: true, value: 3})
        }, 10)
    }) 
}


let doWeHaveMoreTasks = (states) => states.length > 0

let returnIncompletedTasksToTheQueue = (list_of_tasks, task, task_info) => {
    if(!task_info.completed){
        list_of_tasks.unshift(task)
    }

    return list_of_tasks
}

async function task_manager(tasks){
    while(tasks.length > 0){

        const task = tasks.shift() 
        const task_info = await task()

        tasks = returnIncompletedTasksToTheQueue(tasks, task, task_info)

        console.log(`Task number: ${task_info.value} has been completed => ${task_info.completed}.` ) 
        console.log(`Additional info: ${JSON.stringify(task_info,null,4)}`)
    }
}

const _tasks = [task1, task2, task3]
task_manager(_tasks)