Project: Business Process Model and Notation

Related to workflow post.

WorkflowJS is a lightweight and flexible library for building workflows and processes with NodeJS. It allows you to define processes using BPMN 2.0.

This is a JavaScript library for building and executing workflows. It provides a simple, declarative syntax for defining processes, and offers a flexible and extensible framework for handling workflow events and activities.

• Installation
• Concepts
• Quick Start
• Examples
• License

Installation

npm install --save @vhidvz/wfjs

Concepts

*	Concept	Description	Type	Decorator	Required
1	Process	is a BPMN lane, a collection of flow objects.	Class	@Process	Yes
2	Node	is a functionality of Activity in a workflow.	Method	@Node	Yes
3	Activity	is a Flow Object or a Node of a workflow process.	Param	@Act()	Yes
4	Context	is storing the state of the machine during execution.	Param	@Ctx()	No
5	Token	has a history of the execution State, tokens are needed.	Param	@Sign()	No
6	history	is an array of the State of a flow object or node in a token.	–	@Sign()	No
7	State	it contains the state of each node or flows object in history.	–	@Sign()	No
8	Data	is a shared space across the execution context.	Param	@Data()	Maybe
9	Value	is an isolated space for each flow object or node.	Param	@Value()	Maybe

Note: if you return a value in a Node the value is passed to the next available Node as a Value in a specific execution.

Getting Started

Define a BPMN Schema

To define a BPMN schema, you need to create a file with the extension .bpmn and define the schema using the BPMN 2.0 standard or use the online BPMN editor. Here’s an example of a simple BPMN schema:

The full definition of the simple workflow schema .bpmn file located in this link.

Creating a Workflow Instance

To create a new workflow, you need to define a class with methods that represent the different steps of the workflow. You can use decorators to define the nodes and activities of the workflow. Here’s an example of a simple workflow:

import { Act, Node, Process } from "@vhidvz/wfjs/common";
import { EventActivity } from "@vhidvz/wfjs/core";

@Process({ name: 'Simple Workflow' })
class SimpleWorkflow {
  @Node({ name: 'Start' })
  async start(@Act() activity: EventActivity) {
    activity.takeOutgoing();
  }
}

Building and Executing the Workflow

Once you have defined the workflow, you can build and execute it using the WorkflowJS library. Here’s how you can do it:

import { parse, readFile, WorkflowJS } from '@vhidvz/wfjs';

(async () => {
  const workflow = WorkflowJS.build();

  const { context } = await workflow.execute({
    factory: () => new SimpleWorkflow(),
    xml: readFile('./example/simple-workflow.bpmn'),
  });

  console.debug('\nContext is:', JSON.stringify(context.serialize(), null, 2));
})()

More Example

Projects:

• workflow-template is an example of creating a simple workflow microservice.

License

This project is licensed under the MIT License - SEE the LICENSE file for details