JavaScript widget

Files:

File	Purpose
assets/components/reactions/js/web/reactions.js	Widget logic
assets/components/reactions/js/web/reactions.css	Styles

Include

html

<link rel="stylesheet" href="[[++assets_url]]components/reactions/js/web/reactions.css">
<script src="[[++assets_url]]components/reactions/js/web/reactions.js" defer></script>

html

<link rel="stylesheet" href="{'assets_url' | config}components/reactions/js/web/reactions.css">
<script src="{'assets_url' | config}components/reactions/js/web/reactions.js" defer></script>

The Reactions snippet outputs ready markup. The widget initializes automatically when the DOM loads.

Auto-init

The script finds elements with the .reactions-widget class and mounts a widget on each. Re-init of the same element is blocked by data-mounted="true".

Container data attributes

Attribute	Required	Description
data-class-key	yes	Object class (modResource, msProduct…)
data-object-id	yes	Object ID (integer > 0)
data-set	no	Set key, default updown
data-context	no	Context, default web
data-csrf	no	CSRF token. If empty, the widget requests one
data-api	no*	API URL. In snippet SSR filled from [[+api_url]]. Without the attribute: Reactions.config.api, otherwise a path derived from reactions.js (same-origin)
data-types	no	Type names, comma-separated. Attribute missing → catalog from data-set. Empty string → 0 buttons. Extra names outside the set are ignored
data-exclusive	no	1 when the set is exclusive (SSR from the snippet)
data-allow-multiple	no	1 when reactions_allow_multiple is on (SSR)
data-layout	no	auto (default), picker, or bar. auto → picker when there are more than 3 types

API URL resolution order:

1. data-api on the element (snippet sets [[+api_url]])
2. window.Reactions.config.api
3. path from same-origin <script src="…/components/reactions/js/web/reactions.js"> → …/components/reactions/api.php

The Reactions snippet fills data-types with the types actually shown (after the types / reactions_full_types filter). An empty filter result → data-types="", and the widget does not fall back to the full set. Markup example (manual chunk / AJAX):

html

<div
    class="reactions-widget"
    data-api="[[++assets_url]]components/reactions/api.php"
    data-class-key="modResource"
    data-object-id="[[*id]]"
    data-set="full"
    data-types="like,love,fire,star"
    data-context="[[*context_key]]"
></div>

html

<div
    class="reactions-widget"
    data-api="{'assets_url' | config}components/reactions/api.php"
    data-class-key="modResource"
    data-object-id="{$_modx->resource.id}"
    data-set="full"
    data-types="like,love,fire,star"
    data-context="{$_modx->context.key}"
></div>

Override (CDN or non-standard path to api.php):

<script>
  window.Reactions = window.Reactions || {};
  window.Reactions.config = { api: '[[++assets_url]]components/reactions/api.php' };
</script>

or on a specific widget: data-api="[[++assets_url]]components/reactions/api.php".

The Reactions snippet fills required data attributes via the tpl.Reactions.outer chunk. With a custom chunk, keep the reactions-widget class and correct data attributes. data-api is optional.

Manual init

Global object window.Reactions:

// All widgets on the page
Reactions.init();

// Only inside a container (after AJAX load)
const container = document.getElementById('comments');
Reactions.init(container);

init(root) returns an array of ReactionsWidget instances.

Lifecycle

1. Parse data attributes.
2. Request CSRF (GET ?action=csrf) if no token was passed.
3. Load counters (GET ?action=counts).
4. Render: bar (all types in a row) or picker (chips + popover).
5. On click / pick in the popover: optimistic UI → POST ?action=react or DELETE ?action=react.
6. On error: roll back state, refresh CSRF.

Sets in JS

The widget knows emoji for built-in sets:

Set	Types
updown	like 👍, dislike 👎
github	like 👍, dislike 👎, love ❤️, funny 😂, wow 😮, sad 😢, angry 😡, hooray 🎉
full	github + rocket 🚀, eyes 👀, fire 🔥, clap 👏, thinking 🤔, party 🥳, star ⭐, beer 🍺, sparkles ✨, hundred 💯, pray 🙏, muscle 💪, cool 😎, heart_eyes 😍, confused 😕, raised_hands 🙌

For custom sets, server validation still works through the API, but JS renders buttons only when the set matches REACTION_SETS in the bundle. For fully custom sets use server render via the Reactions snippet without JS, or extend the frontend.

Exclusive and sync

The server treats the mode as exclusive when the set is exclusive or reactions_allow_multiple is off. The snippet writes this into data-exclusive / data-allow-multiple. The widget mirrors the same logic: under exclusive, another button clears the previous one (optimistic UI).

Several widgets for the same object (class_key + object_id + context) sync via the reactions:updated event on window after a successful POST/DELETE.

The same event updates sibling .reactions-count nodes (ReactionsCount snippet) for that object — no page reload.

Layout: bar and picker

Mode	When	UI
bar	updown or layout=bar	All types in a row
picker	github / full with layout=auto, or layout=picker	Chips for current reactions + + button and popover grid

Escape and outside click close the popover. Snippet:

modx

[[!Reactions? &set=`github` &layout=`picker`]]
[[!Reactions? &set=`full` &layout=`bar`]]

fenom

{'!Reactions' | snippet : ['set' => 'github', 'layout' => 'picker']}
{'!Reactions' | snippet : ['set' => 'full', 'layout' => 'bar']}

Accessibility

• Container: role="group", aria-label="Reactions".
• Reaction buttons: aria-pressed, aria-label with type name and count.
• Picker: + button with aria-expanded / aria-haspopup. Popover closes on Escape and outside click.
• Errors: role="alert".
• Keyboard: Enter and Space activate the button.

Styling

BEM classes:

Class	Element
.reactions-widget	Container (data-loading, aria-busy while loading)
.reactions-widget__buttons	Button group (bar layout)
.reactions-widget__shell	Summary + trigger wrapper (picker layout)
.reactions-widget__summary	Chips for selected / non-zero reactions
.reactions-widget__trigger	+ button (.is-open when the popover is open)
.reactions-widget__popover	Popover panel
.reactions-widget__picker	Type grid inside the popover
.reactions-widget__picker-button	Type button in the popover
.reactions-widget__button	Reaction button (bar or chip in summary)
.reactions-widget__button.is-active / [aria-pressed="true"]	Selected reaction
.reactions-widget__emoji	Emoji
.reactions-widget__count	Counter (hidden at 0)
.reactions-widget__error	Error message

SSR and JS share the same classes. Override via CSS custom properties: --reactions-border, --reactions-bg, --reactions-active-border, --reactions-muted, and others.

AJAX after dynamic load

Tickets and infinite scroll inject HTML without a full reload. After inserting new comments, call:

document.getElementById('new-comments').addEventListener('load', () => {
    Reactions.init(document.getElementById('new-comments'));
});

Cookie requirements

The widget sends requests with credentials: include. For the ip_cookie strategy the browser must accept the reactions_fid cookie. CSRF is bound to the PHP session.

Build from sources

Sources: frontend/src/. With php _build/build.php the widget builds automatically (assets() step). Manually:

cd frontend
npm install
npm run build

Vite writes artifacts to assets/components/reactions/js/web/ (reactions.js, reactions.css). Those files go into the transport package.