fix: format README and isolate document shell

README.md

@@ -100,20 +100,20 @@ renderTemplate(page, { title: 'Hello' }, { slots: { extra: '<p>More</p>' } });
 
 The email preset calls these. They stay public so a part, or a caller, can use them directly.
 
-| Function                                                                                             | Role                                                                                                                      |
-| ---------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
-| `head({ title?, preview?, styles?, extraHead? })`                                                    | `<head>` with inbox meta, `<title>`, optional preheader, styles, extra HTML                                               |
-| `main({ heading?, bodyText?, ctaLabel?, ctaUrl?, innerHtml? })`                                      | `<main>` with an `<h1>`, a paragraph, and an optional button, or raw `innerHtml`                                          |
-| `footer({ companyName?, unsubscribeUrl? })`                                                          | `<footer>` with the company name and an optional unsubscribe link                                                         |
-| `body({ preheaderHtml?, mainHtml?, footerHtml?, attributes? })`                                      | `<body>` around an optional preheader, main, and footer. Optional raw attributes.                                         |
-| `content({ content? })`                                                                              | A `<div>` around raw HTML. The email shell does not call it                                                               |
+| Function                                                                                             | Role                                                                                                                    |
+| ---------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
+| `head({ title?, preview?, styles?, extraHead? })`                                                    | `<head>` with inbox meta, `<title>`, optional preheader, styles, extra HTML                                             |
+| `main({ heading?, bodyText?, ctaLabel?, ctaUrl?, innerHtml? })`                                      | `<main>` with an `<h1>`, a paragraph, and an optional button, or raw `innerHtml`                                        |
+| `footer({ companyName?, unsubscribeUrl? })`                                                          | `<footer>` with the company name and an optional unsubscribe link                                                       |
+| `body({ preheaderHtml?, mainHtml?, footerHtml?, attributes? })`                                      | `<body>` around an optional preheader, main, and footer. Optional raw attributes.                                       |
+| `content({ content? })`                                                                              | A `<div>` around raw HTML. The email shell does not call it                                                             |
 | `document({ headHtml?, mainHtml?, footerHtml?, doctype?, lang?, htmlAttributes?, bodyAttributes? })` | Doctype, `<html>`, head, and body. Defaults to HTML5 + `lang="en"`. Attributes accept a raw string or a structured map. |
 
 Omitted strings render empty. The button is present only when both `ctaLabel` and `ctaUrl` are set. The unsubscribe link is present only when `unsubscribeUrl` is set.
 
 `bodyText`, `content`, and slot strings may contain inline HTML. Callers own that markup. `escapeHtml` is exported for text and attribute positions; the shell does not call it.
 
-Subpath exports: `@llazyemail/template-runtime-display/escape`, `/head`, `/body`, and `/main`.
+Subpath exports: `@llazyemail/template-runtime-display/escape`, `/head`, `/body`, `/main`, and `/document`.
 
 ## Scripts
 

package.json

@@ -58,6 +58,16 @@
         "types": "./dist/main.d.cts",
         "default": "./dist/main.cjs"
       }
+    },
+    "./document": {
+      "import": {
+        "types": "./dist/document.d.ts",
+        "default": "./dist/document.js"
+      },
+      "require": {
+        "types": "./dist/document.d.cts",
+        "default": "./dist/document.cjs"
+      }
     }
   },
   "files": [

src/index.ts

@@ -42,7 +42,5 @@ export type { BodyProps } from './templates/body/body';
 export { content } from './templates/content/content';
 export type { ContentProps } from './templates/content/content';
 
-export { document } from './templates/document/document';
-export type { DocumentProps, DocumentShellOptions } from './templates/document/document';
-export { openTag, serializeAttributes } from './utils/openTag';
-export type { TagAttributes } from './utils/openTag';
+export { document, mergeShell, openTag, serializeAttributes } from './templates/document';
+export type { DocumentProps, DocumentShellOptions, TagAttributes } from './templates/document';

src/templates/document/index.ts

@@ -0,0 +1,18 @@
+/**
+ * Document shell entry.
+ *
+ * Owns the outer HTML document (doctype, html attributes, body attributes)
+ * and the helpers that build it. Import from the package root or from
+ * `@llazyemail/template-runtime-display/document`.
+ */
+
+export { document } from './document';
+export type { DocumentProps, DocumentShellOptions } from './document';
+
+export { body } from '../body/body';
+export type { BodyProps } from '../body/body';
+
+export { openTag, serializeAttributes } from '../../utils/openTag';
+export type { TagAttributes } from '../../utils/openTag';
+
+export { mergeShell } from './mergeShell';

src/templates/document/mergeShell.ts

@@ -0,0 +1,18 @@
+import type { DocumentShellOptions } from './document';
+
+/**
+ * Merge template-level shell defaults with per-render overrides.
+ * Defined fields on `overrides` win. Omitted fields keep the default.
+ * Explicit `false` / `null` for `lang` is preserved.
+ */
+export function mergeShell(
+  defaults: DocumentShellOptions | undefined,
+  overrides: DocumentShellOptions,
+): DocumentShellOptions {
+  const merged: DocumentShellOptions = { ...defaults };
+  if (overrides.doctype !== undefined) merged.doctype = overrides.doctype;
+  if (overrides.lang !== undefined) merged.lang = overrides.lang;
+  if (overrides.htmlAttributes !== undefined) merged.htmlAttributes = overrides.htmlAttributes;
+  if (overrides.bodyAttributes !== undefined) merged.bodyAttributes = overrides.bodyAttributes;
+  return merged;
+}

src/templates/email/shell.ts

@@ -1,6 +1,6 @@
 import { displayErrors } from '../../runtime/errors';
-import { document } from '../document/document';
-import type { DocumentShellOptions } from '../document/document';
+import { document, mergeShell } from '../document';
+import type { DocumentShellOptions } from '../document';
 import { hasSlot, slot } from '../../runtime/render';
 import type { RenderContext, TemplatePart } from '../../runtime/types';
 import type { EmailProps } from './types';
@@ -26,22 +26,6 @@ export function shellPart(
   };
 }
 
-/**
- * Merge template-level shell defaults with per-render props.
- * Props win when both supply a value.
- */
-export function mergeShell(
-  defaults: DocumentShellOptions | undefined,
-  props: EmailProps,
-): DocumentShellOptions {
-  const merged: DocumentShellOptions = { ...defaults };
-  if (props.doctype !== undefined) merged.doctype = props.doctype;
-  if (props.lang !== undefined) merged.lang = props.lang;
-  if (props.htmlAttributes !== undefined) merged.htmlAttributes = props.htmlAttributes;
-  if (props.bodyAttributes !== undefined) merged.bodyAttributes = props.bodyAttributes;
-  return merged;
-}
-
 /** Place custom part HTML inside `<body>`, after `main` and before `footer`. */
 export function composeEmail(
   parts: Readonly<Record<string, string>>,

src/templates/email/types.ts

@@ -1,5 +1,5 @@
 import type { TemplatePart } from '../../runtime/types';
-import type { DocumentShellOptions } from '../document/document';
+import type { DocumentShellOptions } from '../document';
 
 /** Flat props for the built-in email shell. Every field is optional. */
 export interface EmailProps extends DocumentShellOptions {

tsup.config.ts

@@ -32,6 +32,7 @@ export default defineConfig([
       head: 'src/templates/head/head.ts',
       body: 'src/templates/body/body.ts',
       main: 'src/templates/main/main.ts',
+      document: 'src/templates/document/index.ts',
     },
     format: ['esm', 'cjs'],
     clean: false,