poleeyoodik

Periodically fetch http resources at specific intervals of time and a way to modify the strategy after each run.

Example

You want to fetch an HTTP Resource, every 30 seconds, request timeout at 1 second, restarting the process for 10 times in case of errors:

let periodical = Periodical.run(
  {url: 'https:/jsonplaceholder.typicode.com/posts/1'},
  {
    repetitions: 10,
    interval: 30 * 1000,
    timeout: 1000
  });

periodical.subscribe(
  result => console.log(result),
  error => console.error(error),
  () => console.log('periodical has ended');

Stopping the periodical stream by calling periodical.unsubscribe().

Strategy

Define the strategy to follow when dealing with errors - can retry, repeat or stop a resource, from polling its value.

{
  /*
    default is 0
    alternatives: seconds | minutes | hours | days
    examples: `{seconds: 30}` - every 30 seconds, make the request to fetch resource
  */
  repetitions: 'infinite',

  // minutes `{minutes: 25}`, hours `{hours: 6}`
  interval: {seconds: 30},

  // in case of (some tbd) errors, retry the task for 20 times
  // WILL HAVE A PRECEDENCE OVER `repetitions` and will bypass its value
  // if undefined, default value is 10, or 'infinite' and never stops trying to repeat the task
  retries: 30,

  // when the interval has changed, before the task is called, you can
  // modify the strategy of the next stage
  //
  // The state in this case is the last recorded value of running the
  // task that resulted in some data(eg: 'data.match.odds')
  onInterval: (periodical, state) => {
   if (result.match.isLive)
     return {continue: true, strategy: {interval: {seconds: 5}}}
   if (result.match.hasEnded)
     return {stop: true}
  }
}

Build Setup

# install dependencies
`npm install`

# serve with hot reload at localhost:8080
`npm run dev`

# build for production with minification
`npm run build`