Install

yarn install @sebgroup/green-core

# or use npm
npm install @sebgroup/green-core

Use

There are three main ways you can use Green Core:

• With Lit
• With Angular
• With React

But that said, the components in Green Core are just regular Web Components, so you can use them with or without any framework.

Using Lit

import { css, customElement, LitElement } from 'lit'

// Transitional styles applies the current 2016 design language to the components
import * as ButtonStyles from '@sebgroup/green-core/components/button/button.trans.styles.js'
// This custom `html` template literal tag from Green Core extends the default `lit-html` tag to handle element version scoping.
import { html } from '@sebgroup/green-core/scoping'

// Import the components that you need
import '@sebgroup/green-core/components/button/index.js'

@customElement('my-app')
export class MyApp extends LitElement {
  static styles = css``

  connectedCallback() {
    super.connectedCallback()

    // Register transitional styles to get SEB's current visual design
    ButtonStyles.register()
  }

  render() {
    return html`<gds-button>Click me!</gds-button>`
  }
}

Using Angular

Angular has support for using web components directly in the template. To enable it, you need to do the following:

Add the CUSTOM_ELEMENTS_SCHEMA in the module where you plan to use the components. It is recommended to add this as locally as possible, only on the modules/components where you need it, and not in the app module.

You also need the NggCoreWrapperModule from @sebgroup/green-angular.

In your module:

import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core'
import { NggCoreWrapperModule } from '@sebgroup/green-angular/src/lib/shared'

@NgModule({
    // Add the NggCoreWrapperModule to the `imports` array
    imports: [NggCoreWrapperModule],
    // Add the CUSTOM_ELEMENTS_SCHEMA to the `schemas` array
    schemas: [CUSTOM_ELEMENTS_SCHEMA],
})

In your component:

import '@sebgroup/green-core/components/button/index.js'

// Transitional styles
import * as ButtonStyles from '@sebgroup/green-core/components/button/button.trans.styles.js'

ButtonStyles.register()

Use the web component in your template with the *nggCoreElement directive.

In your template:

<gds-button *nggCoreElement>Click me!</gds-button>

The *nggCoreElement directive comes from the NggCoreWrapperModule you imported above. It has the same purpose as the custom html template tag mentioned in the Lit example above: It handles custom element scoping for you.

Using React

In most cases, we already export React wrappers for these components from the @sebgroup/green-react package. In those cases you can just use those. But you can also easily create your own wrappers using @lit/react.

Here is an example:

import React from 'react'
import { createComponent } from '@lit/react'

import { GdsButton } from '@sebgroup/green-core/component/button/index.js'
import * as ButtonStyles from '@sebgroup/green-core/components/button/button.trans.styles.js'
import { getScopedTagName } from '@sebgroup/green-core/scoping'

ButtonStyles.register()

export const Button = createComponent({
  tagName: getScopedTagName('gds-button'),
  elementClass: GdsButton,
  react: React,
  events: { onClick: 'click' }, // Event callbacks need to be explicitly mapped to DOM events
})

Then you can just use <Button /> like a regular React component.

Documentation

Check out the Storybook (@sebgroup/core) for components and documentation.

Testing

The test suite is split by runtime so Node tooling tests do not run in browser mode.

• Node tests (src/bin/**) for developer tooling such as CLI and MCP server:

  nx run core:test:node

• Browser tests for web components and UI behavior (Chromium + WebKit):

  nx run core:test:browser

• Full suite (same split as CI/local default target):

  nx run core:test

Use core:test:node when working on CLI/MCP code for faster feedback, and core:test:browser when working on components, interactions, or rendering behavior.