15b4a5ebb3
Co-authored-by: Alex Ghiu <Alex.Ghiu@ing.com> Co-authored-by: Thijs Louisse <Thijs.Louisse@ing.com>
248 lines
18 KiB
Markdown
248 lines
18 KiB
Markdown
# Lion Web Components
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Lion web components is a set of highly performant, accessible and flexible Web Components.
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They provide an unopinionated, white label layer that can be extended to your own layer of components.
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For some more details see the [announcement blog post](https://medium.com/ing-blog/ing-open-sources-lion-a-library-for-performant-accessible-flexible-web-components-22ad165b1d3d).
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[](https://www.tickgit.com/browse?repo=github.com/ing-bank/lion)
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## Demos
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We do have a [live Storybook](http://lion-web-components.netlify.com) which shows all our components.
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**Please note:** This project uses Yarn [Workspaces](https://classic.yarnpkg.com/en/docs/workspaces). If you want to run all demos locally you need to get [Yarn](https://classic.yarnpkg.com/en/docs/install) and install all depencies by executing `yarn install`.
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## How to install
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```bash
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npm i @lion/<package-name>
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```
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## Content
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The accessibility column indicates whether the functionality is accessible in its core. Aspects like styling and content determine actual accessibility in usage.
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| Package | Version | Description | Accessibility |
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| ----------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------ | -------------------------- |
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| **-- Buttons --** | | | |
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| [button](./packages/button) | [](https://www.npmjs.com/package/@lion/button) | Button | ✔️ |
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| [switch](./packages/switch) | [](https://www.npmjs.com/package/@lion/switch) | Switch | ✔️ |
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| **-- Forms --** | | | |
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| [form](./packages/form) | [](https://www.npmjs.com/package/@lion/form) | Wrapper for multiple form elements | ✔️ |
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| [field](./packages/field) | [](https://www.npmjs.com/package/@lion/field) | Base Class for all inputs | ✔️ |
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| [fieldset](./packages/fieldset) | [](https://www.npmjs.com/package/@lion/fieldset) | Group for form inputs | ✔️ |
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| [validate](./packages/validate) | [](https://www.npmjs.com/package/@lion/validate) | Validation for form components | n/a |
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| [checkbox](./packages/checkbox) | [](https://www.npmjs.com/package/@lion/checkbox) | Checkbox form element | ✔️ |
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| [checkbox-group](./packages/checkbox-group) | [](https://www.npmjs.com/package/@lion/checkbox-group) | Group of checkboxes | ✔️ |
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| [input](./packages/input) | [](https://www.npmjs.com/package/@lion/input) | Input element for strings | ✔️ |
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| [input-amount](./packages/input-amount) | [](https://www.npmjs.com/package/@lion/input-amount) | Input element for amounts | ✔️ |
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| [input-date](./packages/input-date) | [](https://www.npmjs.com/package/@lion/input-date) | Input element for dates | ✔️ |
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| [input-datepicker](./packages/input-datepicker) | [](https://www.npmjs.com/package/@lion/input-datepicker) | Input element for dates with a datepicker | ✔️ |
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| [input-email](./packages/input-email) | [](https://www.npmjs.com/package/@lion/input-email) | Input element for e-mails | ✔️ |
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| [input-iban](./packages/input-iban) | [](https://www.npmjs.com/package/@lion/input-iban) | Input element for IBANs | ✔️ |
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| [input-range](./packages/input-range) | [](https://www.npmjs.com/package/@lion/input-range) | Input element for a range of values | ✔️ |
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| [radio](./packages/radio) | [](https://www.npmjs.com/package/@lion/radio) | Radio from element | ✔️ |
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| [radio-group](./packages/radio-group) | [](https://www.npmjs.com/package/@lion/radio-group) | Group of radios | ✔️ |
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| [select](./packages/select) | [](https://www.npmjs.com/package/@lion/select) | Simple native dropdown element | ✔️ |
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| [textarea](./packages/textarea) | [](https://www.npmjs.com/package/@lion/textarea) | Multiline text input | ✔️ |
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| **-- Overlays --** | | | |
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| [overlays](./packages/overlays) | [](https://www.npmjs.com/package/@lion/overlays) | Overlay System | ✔️ |
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| [dialog](./packages/dialog) | [](https://www.npmjs.com/package/@lion/dialog) | Dialog element | ✔️ |
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| [tooltip](./packages/tooltip) | [](https://www.npmjs.com/package/@lion/tooltip) | Tooltip element | [#175][i175] |
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| **-- Icons --** | | | |
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| [icon](./packages/icon) | [](https://www.npmjs.com/package/@lion/icon) | Display our svg icons | [#173][i173], [#172][i172] |
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| **-- Navigation --** | | | |
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| [steps](./packages/steps) | [](https://www.npmjs.com/package/@lion/steps) | Multi Step System | n/a |
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| [tabs](./packages/tabs) | [](https://www.npmjs.com/package/@lion/tabs) | Move between a small number of equally important views | n/a |
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| **-- Others --** | | | |
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| [core](./packages/core) | [](https://www.npmjs.com/package/@lion/core) | Core System (exports LitElement, lit-html) | n/a |
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| [calendar](./packages/calendar) | [](https://www.npmjs.com/package/@lion/calendar) | Standalone calendar | [#195][i195], [#194][i194] |
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| [localize](./packages/localize) | [](https://www.npmjs.com/package/@lion/localize) | Localize and translate your application/components | n/a |
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| [ajax](./packages/ajax) | [](https://www.npmjs.com/package/@lion/ajax) | Fetching data via ajax request | n/a |
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## How to use
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### Use a Web Component
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```html
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<script type="module">
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import '@lion/input/lion-input.js';
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</script>
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<lion-input name="firstName"></lion-input>
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```
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### Use a JavaScript system
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```html
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<script type="module">
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import { ajax } from '@lion/ajax';
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ajax.get('data.json').then(response => {
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// most likely you will use response.data
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});
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</script>
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```
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### Extend a Web Component
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```js
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import { LionInput } from '@lion/input';
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class MyInput extends LionInput {}
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customElements.define('my-input', MyInput);
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```
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## Key Features
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- High Performance - Focused on great performance in all relevant browsers with a minimal number of dependencies
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- Accessibility - Aimed at compliance with the WCAG 2.0 AA standard to create components that are accessible for everybody
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- Flexibility - Provides solutions through Web Components and JavaScript classes which can be used, adopted and extended to fit all needs
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## Technologies
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Lion Web Components aims to be future proof and use well-supported proven technology. The stack we have chosen should reflect this.
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- [lit-html](https://lit-html.polymer-project.org) and [lit-element](https://lit-element.polymer-project.org)
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- [npm](http://npmjs.com)
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- [yarn](https://yarnpkg.com)
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- [open-wc](https://open-wc.org)
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- [Karma](https://karma-runner.github.io)
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- [Mocha](https://mochajs.org)
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- [Chai](https://www.chaijs.com)
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- [ESLint](https://eslint.org)
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- [prettier](https://prettier.io)
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- [Storybook](https://storybook.js.org)
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- [ES modules](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import)
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- Lots and lots of tests
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## Rationale
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We know from experience that making high quality, accessible UI components is hard and time consuming:
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it takes many iterations, a lot of development time and a lot of testing to get a generic component that works in every
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context, supports many edge cases and is accessible in all relevant screen readers.
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Lion aims to do the heavy lifting for you.
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This means you only have to apply your own Design System: by delivering styles, configuring components and adding a minimal set of custom logic on top.
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## Coding guidlines
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Check out our [coding guidelines](./docs/README.md) for more detailed information.
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## How to contribute
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Lion Web Components are only as good as its contributions.
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Read our [contribution guide](./CONTRIBUTING.md) and feel free to enhance/improve Lion. We keep feature requests closed while we're not working on them.
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## Scoped elements
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The [CustomElementRegistry](https://developer.mozilla.org/en-US/docs/Web/API/CustomElementRegistry) provides methods for registering custom elements. One of the limitations of working with this global registry is that multiple versions of the same element cannot co-exist. This causes bottlenecks in software delivery that should be managed by the teams and complex build systems. [Scoped Custom Element Registries](https://github.com/w3c/webcomponents/issues/716) is a proposal that will solve the problem. Since this functionality won't be available (especially not cross browser) anytime soon, we've adopted [OpenWC's Scoped Elements](https://open-wc.org/scoped-element).
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Whenever a lion component uses composition (meaning it uses another lion component inside), we
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apply ScopedElementsMixin to make sure it uses the right version of this internal component.
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```js
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import { ScopedElementsMixin, LitElement, html } from '@lion/core';
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import { LionInput } from '@lion/input';
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import { LionButton } from '@lion/button';
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class MyElement extends ScopedElementsMixin(LitElement) {
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static get scopedElements() {
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return {
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'lion-input': LionInput,
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'lion-button': LionButton,
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};
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}
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render() {
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return html`
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<lion-input label="Greeting" name="greeting" .modelValue=${'Hello world'}></lion-input>
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<lion-button>Save</lion-button>
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`;
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}
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}
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```
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### Query selectors
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Since Scoped Elements changes tagnames under the hood, a tagname querySelector should be written
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like this:
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```js
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this.querySelector(getTagName('lion-input', this.constructor.scopedElements));
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```
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### CSS selectors
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Avoid tagname css selectors (we already avoid query selectors internally in lion, but just be aware
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that a selector like `lion-input {...}` will stop working ).
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### Edge cases
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Sometimes we need to render parts of a template to light dom for [accessibility](https://wicg.github.io/aom/explainer.html). For instance we render a node via lit-html that we append to the host element, so
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it gets slotted in the right position.
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In this case, we should also make sure that we also scope the rendered element.
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We can do this as follows:
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```js
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_myLightTemplate() {
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return html`
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This template may be overridden by a Subclasser.
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Even I don't end up in shadow root, I need to be scoped to constructor.scopedElements as well.
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<div>
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<lion-button>True</lion-button>
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<lion-input label="xyz"></lion-input>
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</div>
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`;
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}
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__getLightDomNode() {
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const renderParent = document.createElement('div');
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this.constructor.render(this._myLightTemplate(), renderParent, {
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scopeName: this.localName,
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eventContext: this,
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});
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// this node will be appended to the host
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return renderParent.firstElementChild;
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}
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connectedCallback() {
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super.connectedCallback();
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this.appendChild(this.__getLightDomNode());
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}
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```
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In a less complex case, we might just want to add a child node to the dom.
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```js
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import { ScopedElementsMixin, LitElement, getScopedTagNamegetScopedTagName } from '@lion/core';
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...
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__getLightDomNode() {
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return document.createElement(getScopedTagName('lion-input', this.constructor.scopedElements));
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}
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```
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We encourage you to have a look at [OpenWC's Scoped elements](https://open-wc.org/scoped-elements).
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## Contact
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Feel free to create a github issue for any feedback or questions you might have.
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You can also find us on the Polymer slack in the [#lion](https://polymer.slack.com/messages/CJGFWJN9J/convo/CE6D9DN05-1557486154.187100/) channel.
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You can join the Polymer slack by visiting [https://www.polymer-project.org/slack-invite](https://www.polymer-project.org/slack-invite).
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## Support and issues
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As stated above "support and issues time" is currently rather limited: feel free to open a discussion.
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However, we can not guarantee any response times.
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[i172]: https://github.com/ing-bank/lion/issues/172
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[i173]: https://github.com/ing-bank/lion/issues/173
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[i175]: https://github.com/ing-bank/lion/issues/175
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[i194]: https://github.com/ing-bank/lion/issues/194
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[i195]: https://github.com/ing-bank/lion/issues/195
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