diff --git a/packages/@contentlayer/core/src/generation/generate-types.ts b/packages/@contentlayer/core/src/generation/generate-types.ts
index 1be1bb44..5a355d40 100644
--- a/packages/@contentlayer/core/src/generation/generate-types.ts
+++ b/packages/@contentlayer/core/src/generation/generate-types.ts
@@ -163,9 +163,9 @@ const renderRawType = ({ sourcePluginType }: { sourcePluginType: SourcePluginTyp
 
 const renderFieldDef = (field: FieldDef): string => {
   const canBeUndefined = field.isRequired === false && field.default === undefined
-  return `${field.description ? `  /** ${field.description} */\n` : ''}  ${field.name}: ${renderFieldType(field)}${
-    canBeUndefined ? ' | undefined' : ''
-  }`
+  return `${field.description ? `  /** ${field.description} */\n` : ''}  ${field.name}${
+    canBeUndefined ? '?' : ''
+  }: ${renderFieldType(field)}${canBeUndefined ? ' | undefined' : ''}`
 }
 
 const renderFieldType = (field: FieldDef): string => {
diff --git a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts
index 35924c96..07e5fcf2 100644
--- a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts
+++ b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts
@@ -59,6 +59,31 @@ test('generate-types: simple schema', async (t) => {
   t.snapshot(typeSource)
 })
 
+test('generate-types: simple schema with optional fields', async (t) => {
+  const TestPost = defineDocumentType(() => ({
+    name: 'TestPost',
+    filePathPattern: `**/*.md`,
+    fields: {
+      title: {
+        type: 'string',
+        description: 'The title of the post',
+        required: true,
+      },
+      date: {
+        type: 'date',
+        description: 'The date of the post',
+      },
+    },
+    computedFields: {
+      slug: { type: 'string', resolve: (_) => _._id.replace('.md', '') },
+    },
+  }))
+
+  const typeSource = await renderTypeSource([TestPost])
+
+  t.snapshot(typeSource)
+})
+
 test('generate-types: references with embedded schema', async (t) => {
   const Post = defineDocumentType(() => ({
     name: 'Post',
diff --git a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.md b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.md
index eb6b36b4..709113c7 100644
--- a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.md
+++ b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.md
@@ -72,6 +72,74 @@ Generated by [AVA](https://avajs.dev).
     ␊
      `
 
+## generate-types: simple schema with optional fields
+
+> Snapshot 1
+
+    `// NOTE This file is auto-generated by the Contentlayer CLI␊
+    ␊
+    import type { Markdown, MDX } from 'contentlayer/core'␊
+    import * as Local from 'contentlayer/source-files'␊
+    ␊
+    export { isType } from 'contentlayer/client'␊
+    ␊
+    // export type Image = string␊
+    export type { Markdown, MDX }␊
+    ␊
+    /** Document types */␊
+    export type TestPost = {␊
+      /** File path relative to \`contentDirPath\` */␊
+      _id: string␊
+      _raw: Local.RawDocumentData␊
+      type: 'TestPost'␊
+      /** The title of the post */␊
+      title: string␊
+      /** The date of the post */␊
+      date?: string | undefined␊
+      /** Markdown file body */␊
+      body: Markdown␊
+      slug: string␊
+    }  ␊
+    ␊
+    /** Nested types */␊
+      ␊
+    ␊
+    /** Helper types */␊
+    ␊
+    export type AllTypes = DocumentTypes | NestedTypes␊
+    export type AllTypeNames = DocumentTypeNames | NestedTypeNames␊
+    ␊
+    export type DocumentTypes = TestPost␊
+    export type DocumentTypeNames = 'TestPost'␊
+    ␊
+    export type NestedTypes = never␊
+    export type NestedTypeNames = never␊
+    ␊
+    ␊
+    export interface ContentlayerGenTypes {␊
+      documentTypes: DocumentTypes␊
+      documentTypeMap: DocumentTypeMap␊
+      documentTypeNames: DocumentTypeNames␊
+      nestedTypes: NestedTypes␊
+      nestedTypeMap: NestedTypeMap␊
+      nestedTypeNames: NestedTypeNames␊
+      allTypeNames: AllTypeNames␊
+    }␊
+    ␊
+    declare global {␊
+      interface ContentlayerGen extends ContentlayerGenTypes {}␊
+    }␊
+    ␊
+    export type DocumentTypeMap = {␊
+      TestPost: TestPost␊
+    }␊
+    ␊
+    export type NestedTypeMap = {␊
+    ␊
+    }␊
+    ␊
+     `
+
 ## generate-types: references with embedded schema
 
 > Snapshot 1
diff --git a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.snap b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.snap
index b3c4b6e5..00833cbb 100644
Binary files a/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.snap and b/packages/@contentlayer/source-files/src/__test__/type-generation/basic.spec.ts.snap differ
diff --git a/packages/next-contentlayer/src/hooks/useLiveReload.ts b/packages/next-contentlayer/src/hooks/useLiveReload.ts
index dd0d9611..c6992185 100644
--- a/packages/next-contentlayer/src/hooks/useLiveReload.ts
+++ b/packages/next-contentlayer/src/hooks/useLiveReload.ts
@@ -5,7 +5,7 @@ import React from 'react'
 
 /**
  * Needed as a work around for https://github.com/vercel/next.js/issues/19230
- * Just needed in casese where you're importing from `contentlayer/generated` and use the data directly in your
+ * Just needed in cases where you're importing from `contentlayer/generated` and use the data directly in your
  * React components without going through `getStaticProps` or `getServerSideProps` first.
  */
 export const useLiveReload = () => {