pole

Poll for async resources with an evented interface

Install

$ npm install --save pole

Usage

var poll = require('pole')

var user = pole(function (callback) {
  getUser(callback)  
})

user.onData(console.log)
user.onError(console.error)

user.cancel()
//=> stop polling and ignore any pending responses

API

poll([options], fn) -> object

Returns a polling interface.

onData(listener) -> function

Calls listener when the polling request suceeded with the yielded value. Returns an unlisten function.

onError(listener) -> function

Calls listener when the polling request fails with the yielded error. Returns an unlisten function.

cancel() -> undefined

Stops the polling loop and ignores any pending responses.

options

Type: object

interval

Type: number / function
Default: 0

The interval in milliseconds between successful requests. This parameter can optionally be a function that will be called when data arrives and should return the interval as a number.

retryDelay

Type: number
Default: 1000

The interval in milliseconds between retries after failure. Retries are performed using exponential backoff. Given a retryDelay of 1000, the first retry will be performed after 1 second, then 2, then 4, etc.

maxRetryDelay

Type: number
Default: 30000

The maximum interval in milliseconds between retries.

maxAttempts

Type: number
Default: 5

The number of attempts in total to make, including an initial attempt and maxAttempts - 1 retries with backoff.

fn

Type: function
Arguments: callback<err, data>

A function that will be called with a polling handler. callback is a Node errback.

License

MIT © Ben Drucker