---
title: JavaScript
description: The modules every site's import map already carries, what a site's own
  file may be called and which two names load on their own, and the keys of the site's
  import map.
sidebar:
  order: 18
---

The modules every site's import map already carries, what a site's own file may be called and which two names load on their own, and the keys of the site's import map. Served over MCP as `vizitka://docs/javascript`, and by `describe_vocabulary` with `topic=javascript`.

## Platform modules

What every customer's site gets, and the whole of what a site's import map starts from: Turbo, Stimulus, and the controllers a template can ask for.

`site`, `@hotwired/turbo-rails`, `@hotwired/stimulus`, `@hotwired/stimulus-loading`, `vizitka/live`, `shared/application`, `shared/disclosure_controller`, `shared/disk_image_controller`.

## File names

Lowercase segments of letters, digits and underscores, up to four, the shape `controllers/gallery_controller` and `lib/money` already have. No dot, no hyphen and no leading slash, so a name is never a URL and never a file extension, and stimulus-loading's `controllers/<name>_controller` (hyphens become underscores) is always a name a file can have.

The pattern is `\A[a-z0-9_]+(?:/[a-z0-9_]+){0,3}\z`.

Refused as a first segment: `vizitka`, `shared`, `site`. First segments that are the platform's: `vizitka` is reserved everywhere a site names something, and `shared` and `site` are modules every site's map already carries (`config/importmap/site.rb`).

Taken: `controllers/disclosure_controller`, `controllers/disk_image_controller`. The controller names `site.js` registers for every site, which a site's own file may not take: `disclosure` would be `controllers/disclosure_controller`.

## Conventions

### application

The file imported on every page, when a site has published one.

### controllers/&lt;name&gt;_controller

Where a controller of the site's own lives, the directory stimulus-loading reads. stimulus-loading's own arithmetic: `image-gallery` is `controllers/image_gallery_controller`, `admin--menu` is `controllers/admin/menu_controller`.

## Import map

Keys: `imports`, `integrity`. The two keys a document may have. `scopes` is the standard's third, and it is refused: a scope remaps a name for one directory of modules, and a site has no directory of its own that a scope could mean. A document needs imports, an object from a name to an https:// address.