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Select Rich: Features

Model value

You can set the full modelValue for each option, which includes the checked property for whether it is checked or not.

<lion-option .modelValue=$>Red</lion-option>

Options with HTML

The main feature of this rich select that makes it rich, is that your options can contain HTML.

Many Options with Scrolling

Read only prefilled

You can set the rich select as read only. This will block the user from opening the select.

The readonly attribute is delegated to the invoker for disabling opening the overlay, and for styling purposes.

Disabled Select

You can set the disabled attribute to disable either specific options or the entire select.

If you disable the entire select, the disabled attribute is also delegated to the invoker, similar to readonly.

Render options

The choiceValue can also be a complex value like an Object.

It is up to you how to render this Object in the DOM.

Interaction Mode

You can set the interaction mode to either mac or windows/linux. By default, it will choose based on the user Operating System, but it can be forced.

This changes the keyboard interaction.

Checked index & value

You can get/set the checkedIndex and checkedValue.

No default selection

If you want to set a placeholder option with something like 'Please select', you can of course do this, the same way you would do it in a native select.

Simply put an option with a modelValue that is null.

<lion-option .choiceValue="${null}">select a color</lion-option>

However, this allows the user to explicitly select this option.

Often, you may want a placeholder that appears initially, but cannot be selected explicitly by the user. For this you can use has-no-default-selected attribute.

By default, the placeholder is completely empty in the LionSelectInvoker, but subclassers can easily override this in their extension, by the overriding _noSelectionTemplate() method.

Single Option

If there is a single option rendered, then singleOption property is set to true on lion-select-rich and invoker as well. Invoker also gets single-option which can be used to having desired templating and styling. As in here the arrow is not displayed for single option

When adding/removing options the singleOption will only be true when there is exactly one option.

Custom Invoker

You can provide a custom invoker using the invoker slot. This means it will get the selected value(s) as an input property .selectedElement.

You can use this selectedElement to then render the content to your own invoker.

<lion-select-rich>
  <my-invoker-button slot="invoker"></my-invoker-button>
  ...
</lion-select-rich>

An example of how such a custom invoker class could look like:

class MyInvokerButton extends LitElement() {
  static get properties() {
    return {
      selectedElement: {
        type: Object,
      };
    }
  }

  _contentTemplate() {
    if (this.selectedElement) {
      const labelNodes = Array.from(this.selectedElement.childNodes);
      // Nested html in the selected option
      if (labelNodes.length > 0) {
        // Cloning is important if you plan on passing nodes straight to a lit template
        return labelNodes.map(node => node.cloneNode(true));
      }
      // Or if it is just text inside the selected option, no html
      return this.selectedElement.textContent;
    }
    return ``;
  }

  render() {
    return html`
      <div>
        ${this._contentTemplate()}
      </div>
    `;
  }
}

This example only works if your option elements don't have ShadowDOM boundaries themselves. Cloning deeply only works up until the first shadow boundary.