fix: add missing implementation for isTagManifest and isHtmlBlob type guards

Author: pieh

src/shared/blob-types.cts

@@ -10,9 +10,23 @@ export type HtmlBlob = {
 export type BlobType = NetlifyCacheHandlerValue | TagManifest | HtmlBlob
 
 export const isTagManifest = (value: BlobType): value is TagManifest => {
-  return false
+  return (
+    typeof value === 'object' &&
+    value !== null &&
+    'revalidatedAt' in value &&
+    typeof value.revalidatedAt === 'number' &&
+    Object.keys(value).length === 1
+  )
 }
 
 export const isHtmlBlob = (value: BlobType): value is HtmlBlob => {
-  return false
+  return (
+    typeof value === 'object' &&
+    value !== null &&
+    'html' in value &&
+    'isFallback' in value &&
+    typeof value.html === 'string' &&
+    typeof value.isFallback === 'boolean' &&
+    Object.keys(value).length === 2
+  )
 }

src/shared/blob-types.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from 'vitest'
+
+import { BlobType, HtmlBlob, isHtmlBlob, isTagManifest, TagManifest } from './blob-types.cjs'
+
+describe('isTagManifest', () => {
+  it(`returns true for TagManifest instance`, () => {
+    const value: TagManifest = { revalidatedAt: 0 }
+    expect(isTagManifest(value)).toBe(true)
+  })
+
+  it(`returns false for non-TagManifest instance`, () => {
+    const value: BlobType = { html: '', isFallback: false }
+    expect(isTagManifest(value)).toBe(false)
+  })
+})
+
+describe('isHtmlBlob', () => {
+  it(`returns true for HtmlBlob instance`, () => {
+    const value: HtmlBlob = { html: '', isFallback: false }
+    expect(isHtmlBlob(value)).toBe(true)
+  })
+
+  it(`returns false for non-HtmlBlob instance`, () => {
+    const value: BlobType = { revalidatedAt: 0 }
+    expect(isHtmlBlob(value)).toBe(false)
+  })
+})