From 82bcef8ba0cdf599cd2c780e437ca4ac34d46929 Mon Sep 17 00:00:00 2001
From: zce <w@zce.me>
Date: Mon, 12 Feb 2024 22:16:30 +0800
Subject: [PATCH] fix: defineCollection type inference

close: #39
---
 docs/guide/using-collections.md  |   6 +-
 examples/nextjs/velite.config.ts | 158 ++++++++++++++++---------------
 src/output.ts                    |   3 +-
 src/types.ts                     |  25 ++---
 4 files changed, 101 insertions(+), 91 deletions(-)

diff --git a/docs/guide/using-collections.md b/docs/guide/using-collections.md
index e78dc94..ebcb419 100644
--- a/docs/guide/using-collections.md
+++ b/docs/guide/using-collections.md
@@ -36,10 +36,12 @@ export { default as others } from './others.json'
 ```js [index.d.ts]
 import config from '../velite.config'
 
-export type Post = NonNullable<typeof config.collections>['posts']['schema']['_output']
+type Collections = typeof config.collections
+
+export type Post = Collections['posts']['schema']['_output']
 export declare const posts: Post[]
 
-export type Other = NonNullable<typeof config.collections>['others']['schema']['_output']
+export type Other = Collections['others']['schema']['_output']
 export declare const others: Other[]
 ```
 
diff --git a/examples/nextjs/velite.config.ts b/examples/nextjs/velite.config.ts
index 1336d1d..905ffb8 100644
--- a/examples/nextjs/velite.config.ts
+++ b/examples/nextjs/velite.config.ts
@@ -1,5 +1,5 @@
 import rehypePrettyCode from 'rehype-pretty-code'
-import { defineConfig, s } from 'velite'
+import { defineCollection, defineConfig, s } from 'velite'
 
 const slugify = (input: string) =>
   input
@@ -18,6 +18,85 @@ const meta = s
   })
   .default({})
 
+const options = defineCollection({
+  name: 'Options',
+  pattern: 'options/index.yml',
+  single: true,
+  schema: s.object({
+    name: s.string().max(20),
+    title: s.string().max(99),
+    description: s.string().max(999).optional(),
+    keywords: s.array(s.string()),
+    author: s.object({ name: s.string(), email: s.string().email(), url: s.string().url() }),
+    links: s.array(s.object({ text: s.string(), link: s.string(), type: s.enum(['navigation', 'footer', 'copyright']) })),
+    socials: s.array(s.object({ name: s.string(), icon, link: s.string().optional(), image: s.image().optional() }))
+  })
+})
+
+const categories = defineCollection({
+  name: 'Category',
+  pattern: 'categories/*.yml',
+  schema: s
+    .object({
+      name: s.string().max(20),
+      slug: s.slug('global', ['admin', 'login']),
+      cover: s.image().optional(),
+      description: s.string().max(999).optional(),
+      count
+    })
+    .transform(data => ({ ...data, permalink: `/${data.slug}` }))
+})
+
+const tags = defineCollection({
+  name: 'Tag',
+  pattern: 'tags/index.yml',
+  schema: s
+    .object({
+      name: s.string().max(20),
+      slug: s.slug('global', ['admin', 'login']),
+      cover: s.image().optional(),
+      description: s.string().max(999).optional(),
+      count
+    })
+    .transform(data => ({ ...data, permalink: `/${data.slug}` }))
+})
+
+const pages = defineCollection({
+  name: 'Page',
+  pattern: 'pages/**/*.mdx',
+  schema: s
+    .object({
+      title: s.string().max(99),
+      slug: s.slug('global', ['admin', 'login']),
+      body: s.mdx()
+    })
+    .transform(data => ({ ...data, permalink: `/${data.slug}` }))
+})
+
+const posts = defineCollection({
+  name: 'Post',
+  pattern: 'posts/**/*.md',
+  schema: s
+    .object({
+      title: s.string().max(99),
+      slug: s.slug('post'),
+      date: s.isodate(),
+      updated: s.isodate().optional(),
+      cover: s.image().optional(),
+      video: s.file().optional(),
+      description: s.string().max(999).optional(),
+      draft: s.boolean().default(false),
+      featured: s.boolean().default(false),
+      categories: s.array(s.string()).default(['Journal']),
+      tags: s.array(s.string()).default([]),
+      meta: meta,
+      metadata: s.metadata(),
+      excerpt: s.excerpt(),
+      content: s.markdown()
+    })
+    .transform(data => ({ ...data, permalink: `/blog/${data.slug}` }))
+})
+
 export default defineConfig({
   root: 'content',
   output: {
@@ -27,82 +106,7 @@ export default defineConfig({
     name: '[name]-[hash:6].[ext]',
     clean: true
   },
-  collections: {
-    options: {
-      name: 'Options',
-      pattern: 'options/index.yml',
-      single: true,
-      schema: s.object({
-        name: s.string().max(20),
-        title: s.string().max(99),
-        description: s.string().max(999).optional(),
-        keywords: s.array(s.string()),
-        author: s.object({ name: s.string(), email: s.string().email(), url: s.string().url() }),
-        links: s.array(s.object({ text: s.string(), link: s.string(), type: s.enum(['navigation', 'footer', 'copyright']) })),
-        socials: s.array(s.object({ name: s.string(), icon, link: s.string().optional(), image: s.image().optional() }))
-      })
-    },
-    categories: {
-      name: 'Category',
-      pattern: 'categories/*.yml',
-      schema: s
-        .object({
-          name: s.string().max(20),
-          slug: s.slug('global', ['admin', 'login']),
-          cover: s.image().optional(),
-          description: s.string().max(999).optional(),
-          count
-        })
-        .transform(data => ({ ...data, permalink: `/${data.slug}` }))
-    },
-    tags: {
-      name: 'Tag',
-      pattern: 'tags/index.yml',
-      schema: s
-        .object({
-          name: s.string().max(20),
-          slug: s.slug('global', ['admin', 'login']),
-          cover: s.image().optional(),
-          description: s.string().max(999).optional(),
-          count
-        })
-        .transform(data => ({ ...data, permalink: `/${data.slug}` }))
-    },
-    pages: {
-      name: 'Page',
-      pattern: 'pages/**/*.mdx',
-      schema: s
-        .object({
-          title: s.string().max(99),
-          slug: s.slug('global', ['admin', 'login']),
-          body: s.mdx()
-        })
-        .transform(data => ({ ...data, permalink: `/${data.slug}` }))
-    },
-    posts: {
-      name: 'Post',
-      pattern: 'posts/**/*.md',
-      schema: s
-        .object({
-          title: s.string().max(99),
-          slug: s.slug('post'),
-          date: s.isodate(),
-          updated: s.isodate().optional(),
-          cover: s.image().optional(),
-          video: s.file().optional(),
-          description: s.string().max(999).optional(),
-          draft: s.boolean().default(false),
-          featured: s.boolean().default(false),
-          categories: s.array(s.string()).default(['Journal']),
-          tags: s.array(s.string()).default([]),
-          meta: meta,
-          metadata: s.metadata(),
-          excerpt: s.excerpt(),
-          content: s.markdown()
-        })
-        .transform(data => ({ ...data, permalink: `/blog/${data.slug}` }))
-    }
-  },
+  collections: { options, categories, tags, pages, posts },
   markdown: {
     // https://rehype-pretty-code.netlify.app/
     rehypePlugins: [rehypePrettyCode]
diff --git a/src/output.ts b/src/output.ts
index be4ee7f..d6cf952 100644
--- a/src/output.ts
+++ b/src/output.ts
@@ -39,10 +39,11 @@ export const outputEntry = async (dest: string, configPath: string, collections:
 
   const entry: string[] = []
   const dts: string[] = [`import config from '${configModPath}'\n`]
+  dts.push('type Collections = typeof config.collections\n')
 
   Object.entries(collections).map(([name, collection]) => {
     entry.push(`export { default as ${name} } from './${name}.json'`)
-    dts.push(`export type ${collection.name} = NonNullable<typeof config.collections>['${name}']['schema']['_output']`)
+    dts.push(`export type ${collection.name} = Collections['${name}']['schema']['_output']`)
     dts.push(`export declare const ${name}: ${collection.name + (collection.single ? '' : '[]')}\n`)
   })
 
diff --git a/src/types.ts b/src/types.ts
index e6c5bd9..cc862a9 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -141,15 +141,15 @@ export interface Output {
 /**
  * Collection options
  */
-export interface Collection {
+export interface Collection<T extends Schema> {
   /**
-   * Schema name (singular), for types generation
+   * Collection name (singular), for types generation
    * @example
    * 'Post'
    */
   name: string
   /**
-   * Schema glob pattern, based on `root`
+   * Collection glob pattern, based on `root`
    * @example
    * 'posts/*.md'
    */
@@ -160,7 +160,7 @@ export interface Collection {
    */
   single?: boolean
   /**
-   * Schema
+   * Collection schema
    * @see {@link https://zod.dev}
    * @example
    * s.object({
@@ -170,22 +170,25 @@ export interface Collection {
    *   content: s.string() // from markdown body
    * })
    */
-  schema: Schema
+  schema: T
 }
 
 /**
  * All collections
  */
 export interface Collections {
-  [name: string]: Collection
+  [name: string]: Collection<Schema>
 }
 
+/**
+ * Collection Type
+ */
+export type CollectionType<T extends Collections, P extends keyof T> = T[P]['single'] extends true ? T[P]['schema']['_output'] : Array<T[P]['schema']['_output']>
+
 /**
  * All collections result
  */
-export type Result<T extends Collections> = {
-  [K in keyof T]: T[K]['single'] extends true ? T[K]['schema']['_output'] : Array<T[K]['schema']['_output']>
-}
+export type Result<T extends Collections> = { [P in keyof T]: CollectionType<T, P> }
 
 /**
  * This interface for plugins extra user config
@@ -279,7 +282,7 @@ export interface Config extends Readonly<UserConfig> {
 /**
  * Define a collection (identity function for type inference)
  */
-export const defineCollection = (collection: Collection) => collection
+export const defineCollection = <T extends Schema>(collection: Collection<T>) => collection
 
 /**
  * Define a loader (identity function for type inference)
@@ -289,6 +292,6 @@ export const defineLoader = (loader: Loader) => loader
 /**
  * Define config (identity function for type inference)
  */
-export const defineConfig = <C extends Collections>(config: UserConfig<C>) => config
+export const defineConfig = <T extends Collections>(config: UserConfig<T>) => config
 
 // ↑↑↑ helper identity functions for type inference