Promise Series

A Javascript promise-series function utility. See the promise-series-demo repo for a complete demonstration.

Installtion

With NPM

npm i @cloud-smith/promise-series

With Yarn

yarn add @cloud-smith/promise-series

Example

import { promiseSeries } from '@cloud-smith/promise-series';

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

await promiseSeries(tasks)
  .then(console.log);
  .catch(console.error)

The Dummy Function

For demonstration, we can use a dummy promises that succeeds or fails after a delay, just like a real fetch request.

export const dummyTask = ({ delay, shouldFail, state }: {
  delay: number;
  shouldFail?: Boolean;
  state?: any;
}) => new Promise((resolve, reject) => {
  setTimeout(() => {
    if (state) console.log('Task State: ', state);
    if (shouldFail) reject(`Task simulated failure`);
    else resolve(`Task Success`);
  }, delay);
});

It's possible to import with

import { dummyTask } from '@cloud-smith/promise-series';

Usage

Array Series

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

await promiseSeries({ tasks })
  .then(console.log)
  .catch(console.error);

Named Array Series

const tasks = {
  getApples: () => dummyTask({ delay: 500 }),
  getOrganges: () => dummyTask({ delay: 500 }),
  getGrapes: () => dummyTask({ delay: 500 }),
};

await promiseSeries({ tasks })
  .then(console.log)
  .catch(console.error);

Mixed task types

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => {
    console.log('non-async task testing');
  }
];

await promiseSeries({ tasks })
  .then(console.log)
  .catch(console.error);

Getting state changes

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

const onStateChange = stateUpdate => console;

await promiseSeries({
  tasks,
  onStateChange,
})
  .then(console.log)
  .catch(console.error);

Passing state between tasks

const tasks = [
  state => dummyTask({ delay: 500, state }),
  state => dummyTask({ delay: 500, state }),
  state => dummyTask({ delay: 500, state }),
];

await promiseSeries({ tasks })
  .then(console.log)
  .catch(console.error);

Rollbacks

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

const rollbacks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

await promiseSeries({ tasks, rollbacks })
  .then(console.log)
  .catch(console.error);

Configuration

const config = {
  useLogging: true,
};

const tasks = [
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
  () => dummyTask({ delay: 500 }),
];

await promiseSeries({ config, tasks })
  .then(console.log)
  .catch(console.error);