Asynchronous data sender library

• Asynchronous-first ⚡
• Uses navigator.sendBeacon to send data over HTTP to configured host without waiting for a response. Falls back to XHR when not supported.
• Sends event collection at configured interval or when maximum event collection size is reached.
• Sends all accepted events when the document or a child resource is being unloaded.
• Does not block the process of unloading the document.
• 2.08 kB kB gzipped of minified version.
• Dependency-free 🎉

Download the latest release or install with npm.

npm install metis-data --save

If you linked metis-data directly in your HTML, you can use window.MetisData. If you're using a module bundler, you'll need to import it.

// CommonJS
const MetisData = require('metis-data');

// ES2015
import MetisData from 'metis-data';

Minimal example. See configuration options below.

const analytics = new MetisData({
  api: {
    host: 'https://yourapi.com/path'
  }
}));

analytics.addEvent({
  name: 'your-event-name',
  data: {
    // Data payload
    something: 'mock-data'
  }
});

With default settings, following event will be sent to configured host as POST request within default buffer time (2s).

The payload will be array of event objects converted to a JSON string as following:

[
  {
    "id":"b9e601f6-462a-413b-af98-3f5e28fe2f12",
    "name":"your-event-name",
    "timestamp":1547411367556,
    "data":{
      "something":"mock-data"
    }
  }
]

Each event has unique RFC4122 version 4 compliant UUID by default, which can be overridden with your preferred id.

Also, timestamp is added when the event was added to the event collection. This can be also overriden as following example shows:

analytics.addEvent({
  id: 'your-id', // Must be string
  name: 'your-event-name',
  timestamp: Date.now(),
  data: {
    // Data payload
  }
});

You can set options on metis-data during initialization.

// During initialize
new MetisData({
  api: {
    host: 'https://yourapi.com/path',
    method: 'POST',
    query: {
      param: 123
    }
  },
  bufferTime: 10000,
  batchSize: 32768
});

Describes configured host, where payload is sent.

Describes HTTP request method to the configured host.

Default: (string) POST.

Describes list of query params that will be appended to the host url.

Default: (object) {}.

Describes timespan in what event collection is gathered and sent to configured host.

Default: (integer) 2000 (2s).

Defines maximum batch size for both event collection and event itself.

Default: (integer) 32768 (32 kB)

The library uses navigator.sendBeacon and Object.keys that you might need polyfill for. You can for instance use babel-polyfill in this case.

Contributions are welcome. Please clearly explain the purpose of the PR and follow the current style.

Issues can be resolved quickest if they are descriptive and include both a reduced test case and a set of steps to reproduce.

Licensed under the MIT License © 2019 Genert Org