README.md

bluebird-retry-js

A retry method that accepts parameterless plain-old-javascript functions and bluebird promises.

Accepts a maximum number of attempts, or a termination predicate.

You can scale the retry times with constant, linear, quadratic, and exponential backoff functions. If desired, you may cap the maximum delay between attempts for linear, quadratic, and exponential scaling.

Installation

npm install --save bluebird-retry-js

Usage

'use strict;'

const bluebird = require('bluebird');
const bluebirdretryjs = require('bluebird-retry-js');

var resolves_ok = bluebird.resolve('resolved');
var resolves_rejected = bluebird.reject('rejected');

var fn_ok = () => { return "success" };
var fn_throws = () => { throw new Error("rejected"); };

const RetryAttemptsExceeded = bluebirdretryjs.exceptions.RetryAttemptsExceeded;
const PredicateViolation = bluebirdretryjs.exceptions.PredicateViolation;

bluebirdretryjs.retry(resolves_ok)
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error(err.message);
  });

bluebirdretryjs.retry(fn_ok)
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error(err.message);
  });

bluebirdretryjs.predicatedRetry(bluebird.resolve('predicate example success'), (retryAttemptIndex) => retryAttemptIndex >= 1)
  .then((result) => console.log(result))

bluebirdretryjs.predicatedRetry(bluebird.reject('predicate example rejection'), (retryAttemptIndex) => retryAttemptIndex >= 1)
  .then((result) => console.log(result))
  .catch(PredicateViolation, (err) => {
    console.error(err.message);
  });

bluebirdretryjs.retry(resolves_rejected)
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Default: " + err.message);
  });

bluebirdretryjs.retry(resolves_rejected, 4, bluebirdretryjs.backoff.constant(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Constant: " + err.message);
  });

bluebirdretryjs.retry(resolves_rejected, 4, bluebirdretryjs.backoff.linear(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Linear: " + err.message);
  });

bluebirdretryjs.retry(resolves_rejected, 4, bluebirdretryjs.backoff.quadratic(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Quadratic: " + err.message);
  });

bluebirdretryjs.retry(resolves_rejected, 4, bluebirdretryjs.backoff.exponential(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Exponential: " + err.message);
  });

bluebirdretryjs.retry(fn_throws)
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Default: " + err.message);
  });

bluebirdretryjs.retry(fn_throws, 4, bluebirdretryjs.backoff.constant(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Constant: " + err.message);
  });

bluebirdretryjs.retry(fn_throws, 4, bluebirdretryjs.backoff.linear(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Linear: " + err.message);
  });

bluebirdretryjs.retry(fn_throws, 4, bluebirdretryjs.backoff.quadratic(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Quadratic: " + err.message);
  });

bluebirdretryjs.retry(fn_throws, 4, bluebirdretryjs.backoff.exponential(1))
  .then((result) => console.log(result))
  .catch(RetryAttemptsExceeded, (err) => {
    console.error("Exponential: " + err.message);
  });