An Ash change that writes a slug made by MishkaSlug.slugify/2.

changes do
  change {MishkaSlug.Change, from: :title, into: :slug, language: :language,
          locales: {MyApp.Sites, :languages, []}, keep: [".", "_"]}
end

The change reads :from from the action's arguments or changes and does nothing when it is not there. A value that is not a string, or a title that gives no slug, is a changeset error on :from; the slug attribute is never set to nil or "". The error texts go through Gettext (see MishkaSlug.Messages) in the locale of the calling process. When :max_length is not given, the max_length constraint of the :into attribute is used.

Options

The options of MishkaSlug.slugify/2 (see MishkaSlug.Options) are accepted as they are, except :language and :locales, which take more here. Unknown options and invalid values make init/1 return an error. These are the change's own:

• :from - atom(), required. The attribute or argument the slug is made from, such as :title.

• :into - atom() | nil, default nil. The attribute the slug is written to. Defaults to :from.

• :skip_if_present? - boolean(), default false. Leave the slug alone when the action already sets :into.

• :language - atom() | String.t() | nil, default nil. The text's language: an attribute or argument name read from the changeset (such as :language), or a fixed code.

• :locales - [String.t()] | {module, function, args}, default []. The site's languages: a list, or {module, function, args} called with the changeset first, so a CMS can read them for the changeset's tenant.