[6.x] Autocomplete editor

[jasonvarga]

This adds a simple editor component and fieldtype that includes support for autocomplete mentions.

This will allow us to add configuration fields that make more sense for client facing areas, rather than expecting Antlers to be used.

For example in Forms 2, you'll be able to insert field references within email content.

It's not selectable in the field picker. It's intended for config-facing fields defined in PHP, where the available options can be generated from context, such as a form's own fields.

CleanShot.2026-07-22.at.15.09.58.mp4

How the value is stored

By default, a markdown string with mentions as [[ handle ]] tokens.

email_body: |-
  ## Thanks for getting in touch

  Hi [[ first_name ]],

  We received your message and will reply to [[ email ]] within **two business days**.

Square brackets are markdown special characters, so a literal [[ ]] that an author types is stored escaped, as \[\[ first\_name \]\], and can't be mistaken for a real mention. Text that would otherwise be read as block syntax at the start of a line (- x, # x, 1. x, ---, deep indentation) is escaped too, so it reloads as the text that was typed. The editor itself still speaks ProseMirror. Conversion happens in the fieldtype, at the boundary.

Plain text

Markdown is awkward for simple fields like an email subject, so it can be turned off with markdown: false. The editor is then always inline with no toolbar or formatting, and the value is stored as typed:

subject: 'Hi [[ first_name ]], thanks for your *order*'

The only escaping is a literal [[, stored as \[[, plus any backslashes directly before a [[, which are doubled. enable_line_breaks still applies, and line breaks are stored as newlines.

Option values

Mention values are limited to letters, numbers, underscores, hyphens and periods, which is what the token grammar matches. A static option outside that throws when the field is preloaded. Options from loadOptions arrive at runtime, so invalid ones are dropped with a console warning.

A mention whose option no longer exists, such as a deleted form field, is shown struck through in red.

Resolving mentions

The fieldtype deliberately doesn't resolve them. The values a mention stands for are runtime data it has no access to at augmentation time, so that's the consumer's job:

Mentions::replace($content, ['first_name' => 'John']);

The map doubles as the allowlist, and an unknown key resolves to an empty string. Values are substituted verbatim. Only the consumer knows what context the result ends up in, so escaping belongs to it as well.

To combine mentions with a template pass such as Antlers, give replace() a using: callback:

Mentions::replace($content, $values, using: fn (string $template) => (string) Antlers::parse($template, $data));

Neither order is safe on its own. Parsing first lets submitted values be read as mentions (or have their backslashes eaten), while resolving first turns them into template source. With using:, mentions become inert placeholders, the callback receives the template, and the values are put back afterwards. The callback never sees a value.

The field doesn't offer Antlers itself, so using: is how to run it. Pass replace() the output of augment() or parseMarkdown(), before any Antlers parsing.

Augmentation

In markdown mode, augment() parses the markdown to HTML. Without it the escaping the serializer applies would leak to the front end: text typed as 5 * 2 is stored as 5 \* 2. Inline fields unwrap the single wrapping paragraph so they don't emit a block-level tag.

Mention tokens are left intact for the consumer to resolve. An author's literal [[ is encoded as [[, as are backslashes directly before a token (\), so they can't be confused with a real mention once the markdown escaping is gone. Both render the same in a browser.

parseMarkdown() is public so a consumer holding a raw config string, rather than a Value, gets the same output.

In plain text mode, augment() returns the stored string as is.

Not included

No Forms wiring. This ships the fieldtype and the primitives; Forms 2 consumes them separately.