types

Types

bpmn-js and diagram-js expose type declarations. Editor tooling picks up these declarations to offer advanced completion, and validation. This example shows you to use the type declarations as you embed the libraries.

Usage

Ensure you enabled your editor and environment to provide type hints.

With JavaScript

import BpmnViewer from 'bpmn-js/lib/Viewer';

/**
 * @typedef { import('diagram-js/lib/core/ElementRegistry').default } ElementRegistry
 */

/**
 * @type { HTMLElement }
 */
const container = document.querySelector('#canvas');

const viewer = new BpmnViewer({
  container
});

// type-safe access to components

/**
 * @type { ElementRegistry }
 */
const elementRegistry =  viewer.get('elementRegistry');

const element = elementRegistry.get('MY_TASK');

console.log(element.id); // MY_TASK

Checkout the full example.

With TypeScript

import BpmnViewer from 'bpmn-js/lib/Viewer';

import ElementRegistry from 'diagram-js/lib/core/ElementRegistry';

const container = document.querySelector('#canvas') as HTMLElement;

const viewer = new BpmnViewer({
  container
});

// type-safe access to components
const elementRegistry = viewer.get<ElementRegistry>('elementRegistry');

const element = elementRegistry.get('MY_TASK')!;

console.log(element.id); // MY_TASK

Checkout the full example.

Validation

Use tsc in validation mode to check that you use bpmn-js in an intended manner:

# ensure you have typescript installed
npm install typescript

# check if types are properly used
npx tsc --noEmit --checkJs **/*.js

See also configuring TypeScript.