agent-skills/skills/vercel-composition-patterns/rules/patterns-explicit-variants.md

title, impact, impactDescription, tags

title	impact	impactDescription	tags
Create Explicit Component Variants	MEDIUM	self-documenting code, no hidden conditionals	composition, variants, architecture

Create Explicit Component Variants

Instead of one component with many boolean props, create explicit variant components. Each variant composes the pieces it needs. The code documents itself.

Incorrect (one component, many modes):

// What does this component actually render?
<Composer
  isThread
  isEditing={false}
  channelId='abc'
  showAttachments
  showFormatting={false}
/>

Correct (explicit variants):

// Immediately clear what this renders
<ThreadComposer channelId="abc" />

// Or
<EditMessageComposer messageId="xyz" />

// Or
<ForwardMessageComposer messageId="123" />

Each implementation is unique, explicit and self-contained. Yet they can each use shared parts.

Implementation:

function ThreadComposer({ channelId }: { channelId: string }) {
  return (
    <ThreadProvider channelId={channelId}>
      <Composer.Frame>
        <Composer.Input />
        <AlsoSendToChannelField channelId={channelId} />
        <Composer.Footer>
          <Composer.Formatting />
          <Composer.Emojis />
          <Composer.Submit />
        </Composer.Footer>
      </Composer.Frame>
    </ThreadProvider>
  )
}

function EditMessageComposer({ messageId }: { messageId: string }) {
  return (
    <EditMessageProvider messageId={messageId}>
      <Composer.Frame>
        <Composer.Input />
        <Composer.Footer>
          <Composer.Formatting />
          <Composer.Emojis />
          <Composer.CancelEdit />
          <Composer.SaveEdit />
        </Composer.Footer>
      </Composer.Frame>
    </EditMessageProvider>
  )
}

function ForwardMessageComposer({ messageId }: { messageId: string }) {
  return (
    <ForwardMessageProvider messageId={messageId}>
      <Composer.Frame>
        <Composer.Input placeholder="Add a message, if you'd like." />
        <Composer.Footer>
          <Composer.Formatting />
          <Composer.Emojis />
          <Composer.Mentions />
        </Composer.Footer>
      </Composer.Frame>
    </ForwardMessageProvider>
  )
}

Each variant is explicit about:

• What provider/state it uses
• What UI elements it includes
• What actions are available

No boolean prop combinations to reason about. No impossible states.