#Using and writing plugins

Plugins extend one stage of Core's content pipeline. Choose the stage that owns the behavior you want to change:

Core includes common Markdown syntax, repair, HTML handling, and streaming features. Each guide ends with its built-in plugins. Start by configuring one; write a plugin when you need another behavior.

#Configure a preset

Plugin inputs accept three forms: a plugin list, a configuration object keyed by plugin name, or [pluginList, configObject]. In S, use the tuple form for a static configuration object:

type RepairOptions = [[], RepairConfigs];

const repairs: RepairOptions = [
  [],
  { 'repair-incomplete-image': { strategy: 'discard' } },
];

Pass repairs alongside text and build when creating Core. This hides unfinished images while keeping the other presets.

You can also configure a plugin by class:

pnpm add @fluxdown/core-presets

import type { IPluggable, IRepairPlugin } from '@fluxdown/types';

import { IncompleteImageRepairPlugin } from '@fluxdown/core-presets/repair';

type RepairPlugin = IPluggable<IRepairPlugin, unknown>;

const repairs: RepairPlugin[] = [
  [IncompleteImageRepairPlugin, { strategy: 'discard' }],
];

Existing preset classes keep their place in the list and receive the new options. New plugin classes are added. A keyed configuration overrides options from a class tuple when both are present.

RemarkConfigs, RehypeConfigs, RepairConfigs, and MapperConfigs are provided by the preset type declarations loaded with Core. You do not need to import these names separately.

#Disable or reorder a plugin

All four categories accept disabled and priority:

type RemarkOptions = [[], RemarkConfigs];

const remarks: RemarkOptions = [
  [],
  { 'remark-syntax-soft-endline': { disabled: true } },
];

This keeps ordinary Markdown newlines instead of turning them into hard line breaks. Smaller priority numbers run first within a category; equal values keep declaration order.

#Write a plugin

Remark and rehype plugins adapt unified plugins. Repair plugins visit and update Markdown AST nodes. Mappers use Stative to produce a changing sequence of HAST blocks.

Each guide includes a declaration and shows how to register it:

• Remark plugins
• Repair plugins
• Rehype plugins
• Mapper plugins

Pass plugin classes or mapper functions; Core manages their lifecycle. Keep per-run data inside the transform or state flow so one declaration can serve multiple documents.

Import presets from /remark, /rehype, /repair, or /mapper. The @fluxdown/core-presets package has no root entry point.