Allow for NextURL to parse prefetch requests

vercel · May 24, 2022 · 9d88f8f · 9d88f8f
1 parent 5696f9f
commit 9d88f8f
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Showing 2 changed files with 91 additions and 6 deletions.
diff --git a/packages/next/server/web/next-url.ts b/packages/next/server/web/next-url.ts
@@ -19,6 +19,7 @@ export class NextURL {
     url: URL
     options: Options
     basePath: string
+    buildId?: string
     locale?: {
       defaultLocale: string
       domain?: DomainLocale
@@ -61,6 +62,16 @@ export class NextURL {
   private analyzeUrl() {
     const { headers = {}, basePath, i18n } = this[Internal].options
 
+    if (this[Internal].url.pathname.startsWith('/_next/data/')) {
+      const [buildId, ...rest] = this[Internal].url.pathname
+        .replace(/^\/_next\/data\//, '')
+        .replace(/\.json$/, '')
+        .split('/')
+      this[Internal].buildId = buildId
+      this[Internal].url.pathname =
+        rest[0] !== 'index' ? `/${rest.join('/')}` : '/'
+    }
+
     if (basePath && this[Internal].url.pathname.startsWith(basePath)) {
       this[Internal].url.pathname = replaceBasePath(
         this[Internal].url.pathname,
@@ -102,17 +113,22 @@ export class NextURL {
 
     if (
       this[Internal].locale?.locale &&
-      i18n?.defaultLocale !== this[Internal].locale?.locale &&
-      !this.hasPathPrefix('/api')
+      ((i18n?.defaultLocale !== this[Internal].locale?.locale &&
+        !this.hasPathPrefix('/api')) ||
+        this[Internal].buildId)
     ) {
       pathname = `/${this[Internal].locale?.locale}${pathname}`
     }
 
-    if (this[Internal].basePath) {
-      pathname = `${this[Internal].basePath}${pathname}`
-    }
+    return this[Internal].buildId
+      ? `/_next/data/${this[Internal].buildId}${
+          pathname === '/' ? '/index' : pathname
+        }.json`
+      : `${this[Internal].basePath}${pathname}`
+  }
 
-    return pathname
+  public get buildId() {
+    return this[Internal].buildId
   }
 
   private hasPathPrefix(prefix: string) {

diff --git a/test/unit/web-runtime/next-url.test.ts b/test/unit/web-runtime/next-url.test.ts
@@ -210,3 +210,72 @@ it('does not add locale for api route', () => {
   expect(url.toString()).toEqual(expected)
   expect(url.toJSON()).toEqual(expected)
 })
+
+it('correctly parses a prefetch url', async () => {
+  const url = new NextURL(
+    '/_next/data/1234/en/hello.json',
+    'http://127.0.0.1:3000'
+  )
+  expect(url.buildId).toEqual('1234')
+  expect(url.pathname).toEqual('/en/hello')
+  expect(url.locale).toEqual('')
+  expect(String(url)).toEqual(
+    'http://localhost:3000/_next/data/1234/en/hello.json'
+  )
+})
+
+it('correctly parses a prefetch index url', async () => {
+  const url = new NextURL(
+    '/_next/data/development/index.json',
+    'http://127.0.0.1:3000'
+  )
+  expect(url.pathname).toEqual('/')
+})
+
+it('correctly parses a prefetch url with i18n', async () => {
+  const url = new NextURL(
+    '/_next/data/development/en/hello.json',
+    'http://127.0.0.1:3000',
+    {
+      i18n: {
+        defaultLocale: 'en',
+        locales: ['en', 'es', 'fr'],
+      },
+    }
+  )
+  expect(url.buildId).toEqual('development')
+  expect(url.pathname).toEqual('/hello')
+  expect(url.locale).toEqual('en')
+  expect(String(url)).toEqual(
+    'http://localhost:3000/_next/data/development/en/hello.json'
+  )
+})
+
+it('allows to update the pathname for a prefetch url', async () => {
+  const url = new NextURL(
+    '/_next/data/development/en/hello.json',
+    'http://127.0.0.1:3000',
+    {
+      i18n: {
+        defaultLocale: 'en',
+        locales: ['en', 'es', 'fr'],
+      },
+    }
+  )
+
+  url.pathname = '/foo'
+  expect(String(url)).toEqual(
+    'http://localhost:3000/_next/data/development/en/foo.json'
+  )
+})
+
+it('allows to update the pathname to the root path for a prefetch url', async () => {
+  const url = new NextURL(
+    '/_next/data/development/hello.json',
+    'http://127.0.0.1:3000'
+  )
+  url.pathname = '/'
+  expect(String(url)).toEqual(
+    'http://localhost:3000/_next/data/development/index.json'
+  )
+})