Async Tasks Runner

tiny (~ 1kb gzipped), side-effect free, tree shakable, zero dependencies, and fully typed Tasks Runner. Run your tasks in parallel, serial & pipeline in a more complicated and performant way.

With this module you can run your tasks in 3 different ways:

• Parallel: Run your independent tasks in parallel. The result is an array, like the Promise.allSettled result.
• Serial: Run your independent tasks in sequence. The result is an array, like the Promise.allSettled result.
• Pipeline: Run your dependent tasks in sequence. The result of every task will be passed to the next task.

⚠️ Attention: This package comes without any polyfills. If you want to support an older environment, please polyfills it depending on what you need.

• ES2015
• ES2017 async/await
• ES2020 Promise.allSettled (Just for the ParallelTasksRunner)

Setup

1. Add async-tasks-runner dependency with yarn or npm to your project

yarn add async-tasks-runner

# or

npm install async-tasks-runner

2. Use it everywhere you want

// ES Module
import {createParallelTasksRunner, runParallelTasks, getParallelTasks} from "async-tasks-runner"

// CJS
const {createParallelTasksRunner, runParallelTasks, getParallelTasks} = require("async-tasks-runner")

Runners

Runner	Example
ParallelTasksRunner	See Examples
SerialTasksRunner	See Examples
PipelineTasksRunner	See Examples

Global Helper Functions

Functions	Description	Parameter(s)	Return Value
pushTasks	push tasks to the runner. See pushTasks Section	taskRunnerObject, tasks[]	number: the new length of tasks
spliceTasks	removing or replacing existing tasks and/or adding new elements in place See spliceTasks Section	taskRunnerObject, startIndex, deleteCount, newTasks[]	array: list of removed tasks
getTasksRunnerStatus	current status of the runner. See getTasksRunnerStatus Section	taskRunnerObject	string: status

pushTasks

With this function, you can push new tasks to the runner (like Array.prototype.push()).

pushTasks(taskRunnerObject, ...newTasks[]);

spliceTasks

With this function, you can change the contents of an array by removing or replacing existing elements and/or adding new elements in place (like Array.prototype.splice()).

spliceTasks(taskRunnerObject, start, deleteCount, ...newTasks[] );

getTasksRunnerStatus

With this function, you can get the current status of the runner.

const currentStatus = getTasksRunnerStatus(taskRunnerObject)

This function returns 4 different statuses:

1. standby: The runner is open to adding or removing tasks. This status actually present that the runner is not started yet!
2. pending: Represent that the runner starts pending the tasks and in the meantime, you can't nor add/remove tasks to/from the runner neither reset the runner.
3. fulfilled: Represent that the runner did its job and now you can get the result or reset the runner to add/remove tasks to/from the runner and run them again.
4. rejected: In this status, the runner did its job but with an error in the process, and the whole run is rejected. Like fulfilled status, you can reset the runner to add/remove tasks to/from the runner and run them again.

Examples

Parallel Tasks Runner

You can run your tasks in parallel. the result is an array, like the Promise.allSettled result.

Create

You can create a parallel task runner object by the calling of createParallelTaskRunner. The result will be an object that must be passed as the first argument to any helper functions that you want to use.

import {createParallelTasksRunner} from "async-tasks-runner"
const taskRunnerObject = createParallelTasksRunner(...tasks);

Every task in the ParallelTasksRunner must be a function without a parameter and return a promise.

const url = "https://google.com";

const task1 = () => {
    return fetch(`${url}/first`);
}

const task2 = () => {
    return fetch(`${url}/second`);
}

const taskRunnerObject = createParallelTasksRunner(task1, task2);

Run

Start pending the runner. When it is called, the status changed to pending and when it is done, the status changed to fulfilled. If you run it again, it's not starting to run again and fulfilled with the previous result unless you reset the runner. This means you can start the runner then do some heavy work and call it again to get the result without getting the process blocked! This method returns a promise that resolves after all of the given promises have either been fulfilled or rejected, with an array of objects that each describes the outcome of each promise.

import {runParallelTasks} from "async-tasks-runner"
const result = await runParallelTasks(taskRunnerObject);

// [
//   {status: "fulfilled", value: 33},
//   {status: "fulfilled", value: 66},
//   {status: "fulfilled", value: 99},
//   {status: "rejected",  reason: Error: an error}
// ]

Result of Specific Task

After running the runner (no matter of status is pending or fulfilled or rejected), you can access a specific task with this method. The only parameter of this method is the index of the task. This method returns a Promise that resolves with the task result or is rejected with the current or previous task rejection.

import {getParallelTasks} from "async-tasks-runner"
const result = await getParallelTasks(taskRunnerObject, 0);

Clone

You can clone tasks of your runner and create a new tasks runner.

import {createParallelTasksRunner} from "async-tasks-runner"
const newTaskRunnerObject = createParallelTasksRunner(...taskRunnerObject.tasks);

Serial Tasks Runner

You can run your tasks in sequence. the result is an array, like the Promise.allSettled result.

Create

You can create a serial task runner object by the calling of createSerialTaskRunner. The result will be an object that must be passed as the first argument to any helper functions that you want to use.

import {createSerialTasksRunner} from "async-tasks-runner"
const taskRunnerObject = createSerialTasksRunner(...tasks);

Every task in the SerialTasksRunner must be a function without a parameter and return a promise.

const url = "https://google.com";

const task1 = () => {
    return fetch(`${url}/first`);
}

const task2 = () => {
    return fetch(`${url}/second`);
}

const taskRunnerObject = createSerialTasksRunner(task1, task2);

Run

Start pending the runner. When it is called, the status changed to pending and when it is done, the status changed to fulfilled. If you run it again, it's not starting to run again and fulfilled with the previous result unless you reset the runner. This means you can start the runner then do some heavy work and call it again to get the result without getting the process blocked! This method returns a promise that resolves after all of the given promises have either been fulfilled or rejected, with an array of objects that each describes the outcome of each promise.

import {runSerialTasks} from "async-tasks-runner"
const result = await runSerialTasks(taskRunnerObject);

// [
//   {status: "fulfilled", value: 33},
//   {status: "fulfilled", value: 66},
//   {status: "fulfilled", value: 99},
//   {status: "rejected",  reason: Error: an error}
// ]

Result of Specific Task

After running the runner (no matter of status is pending or fulfilled or rejected), you can access a specific task with this method. The only parameter of this method is the index of the task. This method returns a Promise that resolves with the task result or is rejected with the current or previous task rejection.

import {getSerialTasks} from "async-tasks-runner"
const result = await getSerialTasks(taskRunnerObject, 0);

Clone

You can clone tasks of your runner and create a new tasks runner.

import {createSerialTasksRunner} from "async-tasks-runner"
const newTaskRunnerObject = createSerialTasksRunner(...taskRunnerObject.tasks);

Pipeline Tasks Runner

You can run your tasks in sequence. The result of the currently pending task will be the argument of the next task.

Create

You can create a serial task runner object by the calling of createPipelineTaskRunner. The result will be an object that must be passed as the first argument to any helper functions that you want to use.

import {createPipelineTasksRunner} from "async-tasks-runner"
const taskRunnerObject = createPipelineTasksRunner(...tasks);

Every task in the PipelineTasksRunner must be a function that returns a promise. This function can accept one parameter that will be filled with the previous fulfilled task result.

const url = "https://google.com";

const task1 = (code) => {
    return fetch(`${url}/${code}`);
}

const task2 = (data) => {
    return fetch(data.url);
}

const taskRunnerObject = createPipelineTasksRunner(task1, task2);

Run

With this method, you can start pending the tasks. When it is called, the status changed to pending and when it is done, the status changed to fulfilled if all tasks run successfully or rejected if one of the tasks in the list get failed (and the next tasks don't get run). If you run it again, it's not starting to run again and fulfilled or rejected with the previous result unless you reset the runner. This means you can start the runner then do some heavy work and call it again to get the result without getting the process blocked! This method always returns a promise that resolves with the final task result or rejects with an error. The runPipelineTasks function needs an extra argument for the parameter of the first task function (initial parameter).

import {runPipelineTasks} from "async-tasks-runner"
const result = await runPipelineTasks(taskRunnerObject, firstArgument);

// [
//   {status: "fulfilled", value: 33},
//   {status: "fulfilled", value: 66},
//   {status: "fulfilled", value: 99},
//   {status: "rejected",  reason: Error: an error}
// ]

Result of Specific Task

After running the runner (no matter of status is pending or fulfilled or rejected), you can access a specific task with this method. The only parameter of this method is an index of the task. This method returns a Promise that resolves with the task result or is rejected with the current or previous task failure error.

import {getPipelineTasks} from "async-tasks-runner"
const result = await getPipelineTasks(taskRunnerObject, 0);

Clone

You can clone tasks of your runner and create a new tasks runner.

import {createPipelineTasksRunner} from "async-tasks-runner"
const newTaskRunnerObject = createPipelineTasksRunner(...taskRunnerObject.tasks);

Extra Helper Functions

Functions	Description	Parameter(s)	Return Value
createTimeoutResolve	create a delay with resolve	timeout: number, response: T, cancelToken?: Promise	promise
createTimeoutReject	create a delay with reject	timeout: number, response: T, cancelToken?: Promise	promise
createTaskWithTimeout	create a task with timeout	task: Task, timeout: number	Task

Contribution

1. Fork this repository
2. Install dependencies using yarn install or npm install
3. Making your changes
4. Run the yarn lint command
5. Run the yarn test command
6. Push and make a PR

License

MIT License

Copyright (c) Mohammad Saleh Fadaei (@ms-fadaei)