Portable Abstractions and Patterns for Node.js

This module is a part of the Pip.Services polyglot microservices toolkit. It provides a set of basic patterns used in microservices or backend services. Also the module implemenets a reasonably thin abstraction layer over most fundamental functions across all languages supported by the toolkit to facilitate symmetric implementation.

This module contains the following packages:

• Commands - commanding and eventing patterns
• Config - configuration pattern
• Convert - portable value converters
• Data - data patterns
• Errors- application errors
• Random - random data generators
• Refer - locator inversion of control (IoC) pattern
• Reflect - portable reflection utilities
• Run - component life-cycle management patterns
• Validate - validation patterns

Quick links:

• Configuration Pattern
• Locator Pattern
• Component Lifecycle
• Components with Active Logic
• Data Patterns
• API Reference
• Change Log
• Get Help
• Contribute

Use

Install the NPM package as

npm install pip-services3-commons-node --save

Then you are ready to start using the Pip.Services patterns to augment your backend code.

For instance, here is how you can implement a component, that receives configuration, get assigned references, can be opened and closed using the patterns from this module.

import { IConfigurable } from 'pip-services3-commons-node';
import { ConfigParams } from 'pip-services3-commons-node';
import { IReferenceable } from 'pip-services3-commons-node';
import { IReferences } from 'pip-services3-commons-node';
import { Descriptor } from 'pip-services3-commons-node';
import { IOpenable } from 'pip-services3-commons-node';

export class MyComponentA implements IConfigurable, IReferenceable, IOpenable {
    private _param1: string = "ABC";
    private _param2: number = 123;
    private _anotherComponent: MyComponentB;
    private _opened: boolean = true;

    public configure(config: ConfigParams): void {
        this._param1 = config.getAsStringWithDefault("param1", this._param1);
        this._param2 = config.getAsIntegerWithDefault("param2", this._param2);
    }

    public setReferences(refs: IReferences): void {
        this._anotherComponent = refs.getOneRequired<MyComponentB>(
            new Descriptor("myservice", "mycomponent-b", "*", "*", "1.0")
        );
    }

    public isOpen(): boolean {
        return this._opened;
    }

    public open(correlationId: string, callback: (err: any) => void): void {
        this._opened = true;
        console.log("MyComponentA has been opened.");
        callback(null);
    }

    public close(correlationId: string, callback: (err: any) => void): void {
        this._opened = true;
        console.log("MyComponentA has been closed.");
        callback(null);
    }

}

Then here is how the component can be used in the code

import { ConfigParams } from 'pip-services3-commons-node';
import { References } from 'pip-services3-commons-node';
import { Descriptor } from 'pip-services3-commons-node';

let myComponentA = new MyComponentA();

// Configure the component
myComponentA.configure(ConfigParams.fromTuples(
  'param1', 'XYZ',
  'param2', 987
));

// Set references to the component
myComponentB.setReferences(References.fromTuples(
  new Descriptor("myservice", "mycomponent-b", "default", "default", "1.0", myComponentB
));

// Open the component
myComponentB.open("123", (err) => {
   console.log("MyComponentA has been opened.");
   ...
});

Develop

For development you shall install the following prerequisites:

• Node.js 8+
• Visual Studio Code or another IDE of your choice
• Docker
• Typescript

Install dependencies:

npm install

Compile the code:

tsc

Run automated tests:

npm test

Generate API documentation:

./docgen.ps1

Before committing changes run dockerized build and test as:

./build.ps1
./test.ps1
./clear.ps1

Contacts

The module is created and maintained by Sergey Seroukhov.

The documentation is written by Egor Nuzhnykh, Alexey Dvoykin, Mark Makarychev.