batch run

sol1-configtasks.ts

const chunkSize = 3;
const numberOfTasks = 10;
let tasksSleepInput = Array(numberOfTasks).fill(30).map(v => ({delay: v, index: '' }));
// add indices
Object.keys(tasksSleepInput).forEach(k => tasksSleepInput[Number.parseInt(k)].index = k);

sol1-output.log

[LOG]: "* start running batch 0" 
[LOG]: "  --> Task 0 started" 
[LOG]: "  --> Task 1 started" 
[LOG]: "  --> Task 2 started" 
[LOG]: "  <-- Task 0 finished" 
[LOG]: "  <-- Task 1 finished" 
[LOG]: "  <-- Task 2 finished" 
[LOG]: "* finished running batch 0" 
[LOG]: "* start running batch 3" 
[LOG]: "  --> Task 3 started" 
[LOG]: "  --> Task 4 started" 
[LOG]: "  --> Task 5 started" 
[LOG]: "  <-- Task 3 finished" 
[LOG]: "  <-- Task 4 finished" 
[LOG]: "  <-- Task 5 finished" 
[LOG]: "* finished running batch 3" 
[LOG]: "* start running batch 6" 
[LOG]: "  --> Task 6 started" 
[LOG]: "  --> Task 7 started" 
[LOG]: "  --> Task 8 started" 
[LOG]: "  <-- Task 6 finished" 
[LOG]: "  <-- Task 7 finished" 
[LOG]: "  <-- Task 8 finished" 
[LOG]: "* finished running batch 6" 
[LOG]: "* start running batch 9" 
[LOG]: "  --> Task 9 started" 
[LOG]: "  <-- Task 9 finished" 
[LOG]: "* finished running batch 9" 

sol1.ts

async function solution1() {
    for(let i = 0; i < tasksSleepInput.length; i+= chunkSize) {
        let batch = tasksSleepInput.slice(i, i + chunkSize);
        console.log(`* start running batch ${i}`);
        await Promise.all(batch.map(taskExecutor));
        console.log(`* finished running batch ${i}`);
    }
}

sol2-configtasks.ts

let idx =1, tasksQueue = Array(numberOfTasks).fill(1)
    .map(v => Math.round(Math.random() * 30) + v)
    .map(v => (() => taskExecutor({delay: v, index: `${idx++}` })));

sol2-run.ts

await Promise.all([worker(1), worker(2), worker(3), worker(4)]);

sol2-worker.ts

let worker = async (index: number) => {
    console.log(`worker ${index} is started`);
    while(tasksQueue.length > 0) {
        console.log(`worker ${index} handles task`);
        let task = tasksQueue[0]; // should be atomic
        tasksQueue = tasksQueue.slice(1);
        await task();
        console.log(`worker ${index} finished handling task`);
    }
    console.log(`worker ${index} is retired`);
};

sol2.log

[LOG]: "Total tasks: 10" 
[LOG]: "worker 1 is started" 
[LOG]: "worker 1 handles task" 
[LOG]: "  --> Task 1 started" 
[LOG]: "worker 2 is started" 
[LOG]: "worker 2 handles task" 
[LOG]: "  --> Task 2 started" 
[LOG]: "worker 3 is started" 
[LOG]: "worker 3 handles task" 
[LOG]: "  --> Task 3 started" 
[LOG]: "worker 4 is started" 
[LOG]: "worker 4 handles task" 
[LOG]: "  --> Task 4 started" 
[LOG]: "  <-- Task 4 finished" 
[LOG]: "worker 4 finished handling task" 
[LOG]: "worker 4 handles task" 
[LOG]: "  --> Task 5 started" 
[LOG]: "  <-- Task 3 finished" 
[LOG]: "worker 3 finished handling task" 
[LOG]: "worker 3 handles task" 
[LOG]: "  --> Task 6 started" 
[LOG]: "  <-- Task 1 finished" 
[LOG]: "worker 1 finished handling task" 
[LOG]: "worker 1 handles task" 
[LOG]: "  --> Task 7 started" 
[LOG]: "  <-- Task 2 finished" 
[LOG]: "worker 2 finished handling task" 
[LOG]: "worker 2 handles task" 
[LOG]: "  --> Task 8 started" 
[LOG]: "  <-- Task 6 finished" 
[LOG]: "worker 3 finished handling task" 
[LOG]: "worker 3 handles task" 
[LOG]: "  --> Task 9 started" 
[LOG]: "  <-- Task 5 finished" 
[LOG]: "worker 4 finished handling task" 
[LOG]: "worker 4 handles task" 
[LOG]: "  --> Task 10 started" 
[LOG]: "  <-- Task 8 finished" 
[LOG]: "worker 2 finished handling task" 
[LOG]: "worker 2 is retired" 
[LOG]: "  <-- Task 7 finished" 
[LOG]: "worker 1 finished handling task" 
[LOG]: "worker 1 is retired" 
[LOG]: "  <-- Task 10 finished" 
[LOG]: "worker 4 finished handling task" 
[LOG]: "worker 4 is retired" 
[LOG]: "  <-- Task 9 finished" 
[LOG]: "worker 3 finished handling task" 
[LOG]: "worker 3 is retired" 

task-executor.ts

let taskExecutor = async (task: {delay: number, index: string}) => {
    console.log(`  --> Task ${task.index} started`);
    await sleep(task.delay);
    console.log(`  <-- Task ${task.index} finished`);
};