@tryghost/moleculer-service-from-class NPM

Moleculer Service From Class

This module is used to wrap a standard JS Class as a moleculer service, exposing the public methods as actions on the service. It will also wrap other moleculer services in an object with methods, for each of the services actions and injects them into the class constructor.

This allows us to write generic code, and then use moleculer as the transport layer between services, taking advantage of its load balancing, transporters, logging, tracing & other niceitys

Because moleculer is an asyncronous transport mechanism - all methods MUST be async. Also all methods should accept params as an object with keys - this works with moleculers concept of ctx.params much better.

Private methods are prefixed with an underscore ('_')

Install

npm install @tryghost/moleculer-service-from-class --save

yarn add @tryghost/moleculer-service-from-class

Usage

const srvFromClass = require('@tryghost/moleculer-service-from-class');

class SomeService {
    async capitalize({string}) {
        return string.toUpperCase();
    }
}

class MyAwesomeService {
    constructor({someService, someConfig}) {
        this._someService = someService;
        this._someConfig = someConfig;
    }

    async myCoolMethod({name}) {
        const NAME = await this._someService.capitalize({string: name});

        return `${this._someConfig.greeting}, ${NAME}`;
    }
}

/**
 * Moleculer way
 */

const { ServiceBroker } = require('moleculer');

const broker = new ServiceBroker();
broker.addService(srvFromClass({
    Service: SomeService,
    name: 'some-service'
}));
broker.addService(srvFromClass({
    Service: MyAwesomeService,
    name: 'awesome',
    serviceDeps: {
        someService: 'some-service'
    },
    staticDeps: {
        someConfig: { greeting: 'hello' }
    }
}))

broker.start().then(() => {
    broker.call('awesome.myCoolMethod', {name: 'egg'}).then(console.log);
});


/**
 * Generic way
 */

const awesome = new MyAwesomeService({
    someConfig: { greeting: 'Hello' },
    someService: new SomeService()
});

awesome.myCoolMethod({name: 'egg'}).then(console.log);