@ajimae/retry

Overview

A simple, easy-to-use and zero-dependency javascript async retry package.

Getting Started

$ yarn add @ajimae/retry

or using npm

$ npm install @ajimae/retry

Usage

Basic usage example

// import the package
import { retry } from '@ajimae/retry';

// create the retry wrapper
async function exec() {
  return new Promise((resolve) => {
    // simulate a network call that takes 1.5 seconds
    setTimeout(() => {
      resolve({
        statusCode: 200,
        message: 'success',
        data: {
          name: 'meeky',
          age: 150
        }
      })
    }, 1500);
  });
};

// create a predicate function
function predicate(response, retryCount) {
  /**
   * access the retry count using the `retryCount` param,
   * once the condition or conditions specified in this
   * predicate function is met or the `maxRetries` is exhausted
   * (retryCount == maxRetries) the retry exits.
   */
  return (response.statusCode != 200);
}

(async function main() {
  const result = await retry(exec, predicate, { maxRetries: 5 })
})();

Package API

Retry function

The package exposes a retry function which is a simple function that takes in three (3) arguments and returns a generic promise.

// exposed retry function
function retry<T>(
  fn: () => Promise<T>,
  predicate: (response: T, retryCount: number) => boolean,
  retryPolicy?: Partial<RetryPolicy>
): Promise<T>;

The retry function arguments

execute

• A function (usually an (anonymous) async function) that returns a promise-like value.

async function execute(): Promise<T> {
  return T
}

predicate

• A predicate (function) takes in the response (the result from the execute function) as the first argument, a retryCount as the second argument and returns a boolean.

function predicate(response: T, retryCount: number): boolean {
  return true | false
}

retryPolicy

• An object that defines how the retry should be performed.

import { RetryPolicy } from '@ajimae/retry'

const retryPolicy: Partial<RetryPolicy> = {
  maxRetries: number;
  backoff: boolean;
  retryDelay: number;
  maxDelay: number;
}

Note: The package also exposes the typescript type RetryPolicy

import { retry, RetryPolicy } from '@ajimae/retry'

Author

Chukwuemeka Ajima - @ajimae

License

This project is licensed under the MIT License.

See LICENSE for more information.