@gar/promise-retry

This is a fork of promise-retry. See the CHANGELOG.md for more info. It also inlines and updates the original retry package that was being promisified.

Retries a function that returns a promise, leveraging the power of the retry module to the promises world.

There's already some modules that are able to retry functions that return promises but they were rather difficult to use or do not offer an easy way to do conditional retries.

Installation

$ npm install promise-retry

Usage

retry(fn(retry, number, operation), [options])

Calls fn until the returned promise ends up fulfilled or rejected with an error different than a retry error. The options argument is an object which maps to the original retry module options:

• retries: The maximum amount of times to retry the operation. Default is 10.
• factor: The exponential factor to use. Default is 2.
• minTimeout: The number of milliseconds before starting the first retry. Default is 1000.
• maxTimeout: The maximum number of milliseconds between two retries. Default is Infinity.
• randomize: Randomizes the timeouts by multiplying with a factor between 1 to 2. Default is false.
• forever: Whether to retry forver, default is false.
• unref: Whether to unref the underlying setTimeouts.
• maxRetryTime: Maximum number of milliseconds that the retried operation is allowed to run.

options can also be a Number, which is effectively the same as pasing { retries: Number }

The fn function will be called with the following parameters:

• A retry function as its first argument that should be called with an error whenever you want to retry fn. The retry function will always throw an error.
• The current retry number being attempted
• The retry operation object itself from which will allow you to call things like operation.reset()

If there are retries left, it will throw a special retry error that will be handled internally to call fn again. If there are no retries left, it will throw the actual error passed to it.

Example

const { retry } = require('@gar/promise-retry');

// Simple example
retry(function (retry, number) {
    console.log('attempt number', number);

    return doSomething()
    .catch(retry);
})
.then(function (value) {
    // ..
}, function (err) {
    // ..
});

// Conditional example
retry(function (retry, number) {
    console.log('attempt number', number);

    return doSomething()
    .catch(function (err) {
        if (err.code === 'ETIMEDOUT') {
            retry(err);
        }

        throw err;
    });
})
.then(function (value) {
    // ..
}, function (err) {
    // ..
});

Tests

$ npm test

License

Released under the MIT License.