Make next export respect experimental.exportTrailingSlash (#6752)

* Add --no-subfolders argument to next export

* Use experimental.exportTrailingSlash instead of a cli flag

* Add experimental.exportTrailingSlash documentation

* Add tests for export with experimental.exportTrailingSlash

* Remove docs

* Remove comment

packages/next/export/index.js

@@ -24,6 +24,7 @@ export default async function (dir, options, configuration) {
   const concurrency = options.concurrency || 10
   const threads = options.threads || Math.max(cpus().length - 1, 1)
   const distDir = join(dir, nextConfig.distDir)
+  const subFolders = nextConfig.experimental.exportTrailingSlash
 
   if (nextConfig.target !== 'server') throw new Error('Cannot export when target is not server. https://err.sh/zeit/next.js/next-export-serverless')
 
@@ -139,7 +140,8 @@ export default async function (dir, options, configuration) {
             outDir,
             renderOpts,
             serverRuntimeConfig,
-            concurrency
+            concurrency,
+            subFolders
           })
           worker.on('message', ({ type, payload }) => {
             if (type === 'progress' && progress) {

packages/next/export/worker.js

@@ -26,7 +26,8 @@ process.on(
     outDir,
     renderOpts,
     serverRuntimeConfig,
-    concurrency
+    concurrency,
+    subFolders
   }) => {
     const sema = new Sema(concurrency, { capacity: exportPaths.length })
     try {
@@ -47,6 +48,9 @@ process.on(
         })
 
         let htmlFilename = `${path}${sep}index.html`
+
+        if (!subFolders) htmlFilename = `${path}.html`
+
         const pageExt = extname(page)
         const pathExt = extname(path)
         // Make sure page isn't a folder with a dot in the name e.g. `v1.2`

test/integration/export-subfolders/next.config.js

+module.exports = {
+  experimental: {
+    exportTrailingSlash: false
+  }
+}

test/integration/export-subfolders/pages/about.js

+export default () => (
+  <p>I am an about page</p>
+)

test/integration/export-subfolders/pages/index.js

+export default () => (
+  <p>I am a home page</p>
+)

test/integration/export-subfolders/pages/posts/index.js

+export default () => (
+  <p>I am a list of posts</p>
+)

test/integration/export-subfolders/pages/posts/single.js

+export default () => (
+  <p>I am a single post</p>
+)

test/integration/export-subfolders/test/index.test.js

+/* eslint-env jest */
+/* global jasmine */
+import fs from 'fs'
+import { join } from 'path'
+import cheerio from 'cheerio'
+import { promisify } from 'util'
+import {
+  nextBuild,
+  nextExport
+} from 'next-test-utils'
+
+jasmine.DEFAULT_TIMEOUT_INTERVAL = 1000 * 60 * 5
+const readFile = promisify(fs.readFile)
+const access = promisify(fs.access)
+const appDir = join(__dirname, '../')
+const outdir = join(appDir, 'out')
+
+describe('Export experimental.exportTrailingSlash set to false', () => {
+  beforeAll(async () => {
+    await nextBuild(appDir)
+    await nextExport(appDir, { outdir })
+  })
+
+  it('should export pages as [filename].html instead of [filename]/index.html', async () => {
+    expect.assertions(6)
+
+    await expect(access(join(outdir, 'index.html'))).resolves.toBe(undefined)
+    await expect(access(join(outdir, 'about.html'))).resolves.toBe(undefined)
+    await expect(access(join(outdir, 'posts.html'))).resolves.toBe(undefined)
+    await expect(access(join(outdir, 'posts', 'single.html'))).resolves.toBe(undefined)
+
+    const html = await readFile(join(outdir, 'index.html'))
+    const $ = cheerio.load(html)
+    expect($('p').text()).toBe('I am a home page')
+
+    const htmlSingle = await readFile(join(outdir, 'posts', 'single.html'))
+    const $single = cheerio.load(htmlSingle)
+    expect($single('p').text()).toBe('I am a single post')
+  })
+})