Installation

yarn add tasko
npm install tasko

Terminology

Tasko is inspired by Behavior tree' control flow. It doesn't rely on a time-based execution (tick).

Task creators

A task creator is a function that creates a task.

Parameters

| Properties | Type | Details | | ----------- | -------- | ------------------------------------------------------------------------------- | | success | function | A callback function to notify the parent the task succeeded. | | | | It takes an optional parameter to be propagated which simulate a send call. | | fail | function | A callback function to notify the parent the task failed. | | | | It takes an optional parameter to be propagated which simulate a send call. | | send | function | A function to send something to the parent. | | | | It takes an required parameter to be propagated. |

Returns

A Task.

Tasks

A task is an object which can be run a process and/or be cancelled.

Properties

| Properties | Type | Details | | ---------- | -------- | ------------------------------------------------------------------------- | | name | string | Task name | | run | function | Called by the parent to run the task with optional spread params | | cancel | function | Called by the parent to cancel the task, before or after running the task |

Usage

/**
 * Create a successful task
 *
 * @param {function} success - The callback to succeed with an optional param
 * @param {function} fail - The callback to fail with an optional param
 * @param {function} message - Send a message to the parent
 *
 * @returns {object} - A task
 */
const createSuccessfulTask = (success, fail, send) => ({
  name: 'success',
  run(...params) {
    send(`the task is running with params: ${JSON.stringify(params)}`)
    success('success')
  },
  cancel: () => {
    // noop
  },
})

Decorators

A decorator is a function which enhances the original task behavior.

Parameter

A task creator to enhance.

Returns

A task creator enhanced.

Usage

/**
 * Makes a task always succeeds
 *
 * @param {function} taskCreator - task creator to enhance
 *
 * @returns {function} - Enhanced task creator
 */
const alwaysSucceed = (taskCreator) => (succeed, _, send) => {
  const task = taskCreator(succeed, succeed, send)

  return {
    ...task,
    name: decorateName('alwaysSucceed', task.name), // @alwaysSucceed(task-name)
  }
}

See existing decoractors that you can use import https://github.com/DevSide/tasko/blob/master/src/decorator.js

Composites

A composite (or branch) is a task which orchestrates other tasks with an execution mode and an exit condition.

Execution modes

It determined how a composite task should run its children.

• serie: one task after another
• parallel: only works if the tasks run asynchronously, serie otherwise

Exit conditions

It determined how a composite task will succeed or fail based on its children.

• selector: this task immediately succeeds if a child has succeeded, fails if all its children have failed
• sequence: this task immediately fails if a child has failed, succeeds if all its children have succeeded
• all: this task runs all its children, it fails if a child has failed, succeeds otherwise

Parameter

A (spread) list of task creators to execute.

Returns

A task creators.

Available composites

import {
  serieSequence,
  serieSelector,
  serieAll,
  parallelSequence,
  parallelSelector,
  parallelAll,
} from 'tasko/composite'

Usage

import { serieSequence } from 'tasko/composite'
import { noop } from 'tasko/util'

const think = (success, fail, send) => ({
  name: 'think',
  run() {
    send(`I'm thinking`)
    success('Done')
  },
  cancel: noop,
})

const thinkings = serieSequence(think, think)

thinkings(
  () => console.log('Process succeeded !'),
  () => console.log('Process failed !'),

  // composites lift up every child messages sent, the 2nd argument is the unique child name
  (message, taskName) => console.log(taskName + ':', message),
).run()

Logs

think: I'm thinking
think: Done
think: I'm thinking
think: Done
Process succeeded !

More examples