Shoelace and Rails UJS

TL;DR:

For usage with data-remote, like for launching modals, use data-url to set the path. For regular link buttons, use the href attribute.

<sl-button data-url="some_path" data-remote="true" data-toggle="modal" data-dismissible="true" data-close-others="true">Modal launcher</sl-button>

<sl-button href="some_path">Regular link button</sl-button>

sl-button[
  data-url="some_path"
  data-remote="true"
  data-toggle="modal"
  data-dismissible="true"
  data-close-others="true"
]
  | Modal launcher

sl-button href="some_path" Regular link button

Detailed explanation

For the most part, Shoelace components function like regular html elements, including tha ability to add the data- attributes used by Rails to inject functionality. Where that breaks down is when Rails expects only a certain subset of elements to have those attributes. One example of this is UJS’s handling of button clicks, which, by default, only detects HTML <button> elements. <sl-button> does contain a <button> element (or an <a> tag if it’s a link button), but those are hidden in the shadow dom, where UJS can’t find them.

Fortunately, Rails UJS is in JavaScript, which means the query selectors it uses to find elements on the page is writeable. All we have to do is directly modify that selector, and UJS will treat <sl-button> elements like other <button>s. We have to do that before Rails is initialized so that UJS has a chance to run.

Here’s the code that overrides the UJS selectors. (It’s already in shared-ui, this is just for posterity.)

import Rails from '@rails/ujs';

Rails.buttonClickSelector = {
  selector:
    Rails.buttonClickSelector.selector + ', sl-button[data-remote]:not([form]), sl-button[data-confirm]:not([form])',
  exclude: 'form button, form sl-button'
};
Rails.linkClickSelector +=
  ', sl-button[href][data-confirm], sl-button[href][data-method], sl-button[href][data-remote]:not([disabled]), sl-button[href][data-disable-with], sl-button[href][data-disable]';
Rails.inputChangeSelector += ', sl-select[data-remote], sl-input[data-remote], sl-textarea[data-remote]';
Rails.formInputClickSelector +=
  ', form:not([data-turbo=true]) sl-input[type=submit], form:not([data-turbo=true]) sl-input[type=image], form:not([data-turbo=true]) sl-button[type=submit], form:not([data-turbo=true]) sl-button:not([type]), sl-input[type=submit][form], sl-input[type=image][form], sl-button[type=submit][form], sl-button[form]:not([type])';
Rails.formDisableSelector +=
  ', sl-input[data-disable-with]:enabled, sl-button[data-disable-with]:enabled, sl-textarea[data-disable-with]:enabled, sl-input[data-disable]:enabled, sl-button[data-disable]:enabled, sl-textarea[data-disable]:enabled';
Rails.formEnableSelector +=
  ', sl-input[data-disable-with]:disabled, sl-button[data-disable-with]:disabled, sl-textarea[data-disable-with]:disabled, sl-input[data-disable]:disabled, sl-button[data-disable]:disabled, sl-textarea[data-disable]:disabled';
Rails.fileInputSelector += ', sl-input[name][type=file]:not([disabled])';
Rails.linkDisableSelector += ', sl-button[href][data-disable-with], sl-button[href][data-disable]';
Rails.buttonDisableSelector += ', sl-button[data-remote][data-disable-with], sl-button[data-remote][data-disable]';

Rails.start();

Because we’ve modified the selectors, you can now use an <sl-button> like so:

content_tag("sl-button",
  "Button label",
  data: {
    "remote" => true,
    "url" => some_path,
    "toggle" => "modal",
    "dismissible" => true,
    "close-others" => true,
  })

Or, in Slim:

sl-button[
  data-url="some_path"
  data-remote="true"
  data-toggle="modal"
  data-dismissible="true"
  data-close-others="true"
]
  | Button label

Note that UJS expects the URL for a button with data-remote to be set in the data attributes rather than the href we would normally use. (You can still set the href, but it won’t do anything.) For regular link buttons

A useful way to debug

Rails provides a delegate method that allows you to intercept events emitted by elements matching a selector. This is very useful for seeing which elements are dispatching which events.

import Rails from '@rails/ujs';

Rails.delegate(document, 'sl-button[href]', 'click', e => {
  console.log('sl-button[href]:e.target.href', e.target.href, e.target.dataset);
});

Rails.delegate(document, '[data-remote]', 'click', e => {
  console.log('[data-remote]:e.target.href', e.target.href);
});