Jarvus

Small (just over 1kb) package for executing arbitrary actions (operations, work) based on specified data. Work is done asynchronously and in a decentralized fashion.

Installation

npm install @almgong/jarvus

Usage

All work-to-do is represented by Action classes in Jarvus. After defining such a class, one simply needs to #add an instance of the action to Jarvus' registry.

Let's go through a real(ish) world example.

We have an ML model that returns text content based on some input. When the model returns 'car', we want to log a car result; when the model returns 'bicycle', we want to log a bicycle result instead.

Our car-Action class

import { Action } from '@almgong/jarvus';

class CarFoundAction extends Action {
  shouldRun(payload) {
    payload.text === 'car';
  }

  execute(payload) {
    MyLoggerService.notify(
      { type: 'vehicle/car', originalImg: payload.imgUrl }
    );
  }
}

and for more flavor, our bicycle-Action class

import { Action } from '@almgong/jarvus';

class BicycleFoundAction extends Action {
  shouldRun(payload) {
    // our model is not quite as accurate when it comes to
    // detecting bikes
    payload.text === 'bicycle' && payload.confidence > 0.98;
  }

  execute(payload) {
    MyLoggerService.notify(
      {
        type: 'vehicle/bicycle',
        originalImg: payload.imgUrl,
        confidence: payload.confidence
      }
    );
  }
}

And to wire it all up

import Jarvus from '@almgong/jarvus';

const jarvus = new Jarvus();
jarvus.add(new CarFoundAction('cars'));
jarvus.add(new BicycleFoundAction('bicycles));

...

jarvus.send({ text: 'car', confidence: .82, imgUrl: '...' }); // executes our car action

jarvus.send({ text: 'bicycle', confidence: .82, imgUrl: '...' }); // does not execute any action
jarvus.send({ text: 'bicycle', confidence: .91, imgUrl: '...' }); // executes our bicycle action

Actions

Action subclasses must define two methods:

shouldRun(payload: object) : boolean - whether the action should run

execute(payload: object) : void - what the action should do if it should run

The payload object in both methods will be the same for any given Action, and but can be customized across Actions.

All Action instances must have a unique identifier, specified on instantiation. This helps guard against duplicate registrations and provides a path for debugging and metric gathering.

Jarvus API

The Jarvus class exposes three public methods:

add(action: Action) : void - add the action to the registry

remove(action: Action) : void - remove the action from the registry

send(payload: object) : void - dispatch an arbitrary payload and let actions determine if they need to run

License

MIT