@jsier/retrier

Promise based retry logic

A simple, efficient and lightweight package without external dependencies which helps quickly implement JavaScript promise based retry logic. Retrier class is built with TypeScript (preserves full compatibility with pure JavaScript) and exposes intuitive and easy-to-use API.

Supports:

• First attempt delay
• Delay between attempts
• Limiting number of attempts
• Callback to stop retrying if some condition is met (e.g. specific error is encountered)
• Callback to keep retrying if some condition is met (e.g. resolved value is unsatisfactory)

Getting Started

$ npm install @jsier/retrier --save

Usage

Retrier constructor as a first argument expects function which returns a promise. Second argument is optional and expects retry options object.

import { Retrier } from '@jsier/retrier';

const options = { limit: 5, delay: 2000 };
const retrier = new Retrier(options);
retrier
  .resolve(attempt => new Promise((resolve, reject) => reject('Rejected!')))
  .then(
    result => console.log(result),
    error => console.error(error) // After 5 attempts logs: "Rejected!"
  );

Retry Options

By default, the retrier will retry until provided promise resolves successfully or until retry limit is reached. To override the defaults please see retry options below:

Property | Description | Type | Default --- | --- | --- | --- limit | Number of attempts. | number | 1 delay | Delay between attempts in milliseconds. | number | 0 firstAttemptDelay | Delay first attempt. | number | 0 keepRetryingIf | Treat resolved value as invalid and keep retrying - if provided function returns truthy value. Example: keepRetryingIf: (response, attempt) => response.status === 202; | Function | undefined stopRetryingIf | Stop retrying (reject) if specific error - (provided function returns truthy value). Example: stopRetryingIf: (error, attempt) => error.status === 500; | Function | undefined

Support

All suggestions and improvements are welcomed and appreciated.

License

The MIT License.