Show warning if next export detects an API route

errors/api-routes-static-export.md

@@ -0,0 +1,13 @@
+# API routes in Static export
+
+#### Why This Warning Occurred
+
+An `exportPathMap` path was matched to an API route. `next export` will not prerender API routes to HTML.
+
+#### Possible Ways to Fix It
+
+Remove any paths using API routes from your `exportPathMap` in `next.config.js`.
+
+### Useful Links
+
+- [Static HTML export](https://github.com/zeit/next.js#static-html-export)

packages/next/export/index.js

@@ -4,6 +4,7 @@ import { recursiveCopy } from '../lib/recursive-copy'
 import mkdirpModule from 'mkdirp'
 import { resolve, join } from 'path'
 import { existsSync, readFileSync } from 'fs'
+import chalk from 'chalk'
 import loadConfig, {
   isTargetLikeServerless
 } from 'next-server/dist/server/config'
@@ -36,7 +37,6 @@ export default async function (dir, options, configuration) {
   const threads = options.threads || Math.max(cpus().length - 1, 1)
   const distDir = join(dir, nextConfig.distDir)
   const subFolders = nextConfig.exportTrailingSlash
-  let apiPage = false
 
   if (!options.buildExport && nextConfig.target !== 'server') {
     throw new Error(
@@ -62,19 +62,12 @@ export default async function (dir, options, configuration) {
   for (const page of pages) {
     // _document and _app are not real pages
     // _error is exported as 404.html later on
-    const isApiRoute = page.match(API_ROUTE)
-
-    // Warn about API pages export
-    if (isApiRoute && !apiPage) {
-      apiPage = true
-      log(`  API pages are not supported in export`)
-    }
-
+    // API Routes are Node.js functions
     if (
       page === '/_document' ||
       page === '/_app' ||
       page === '/_error' ||
-      isApiRoute
+      page.match(API_ROUTE)
     ) {
       continue
     }
@@ -149,10 +142,24 @@ export default async function (dir, options, configuration) {
   })
   exportPathMap['/404.html'] = exportPathMap['/404.html'] || { page: '/_error' }
   const exportPaths = Object.keys(exportPathMap)
+  const filteredPaths = exportPaths.filter(
+    // Remove API routes
+    route => !exportPathMap[route].page.match(API_ROUTE)
+  )
+  const hasApiRoutes = exportPaths.length !== filteredPaths.length
+
+  // Warn if the user defines a path for an API page
+  if (hasApiRoutes) {
+    log(
+      chalk.yellow(
+        '  API pages are not supported by next export. https://err.sh/zeit/next.js/api-routes-static-export'
+      )
+    )
+  }
 
-  const progress = !options.silent && createProgress(exportPaths.length)
+  const progress = !options.silent && createProgress(filteredPaths.length)
 
-  const chunks = exportPaths.reduce((result, route, i) => {
+  const chunks = filteredPaths.reduce((result, route, i) => {
     const worker = i % threads
     if (!result[worker]) {
       result[worker] = { paths: [], pathMap: {} }

test/integration/api-support/test/index.test.js

@@ -10,7 +10,6 @@ import {
   renderViaHTTP,
   nextBuild,
   nextStart,
-  runNextCommand,
   File
 } from 'next-test-utils'
 import json from '../big.json'
@@ -286,17 +285,6 @@ function runTests (serverless = false) {
     }
   })
 
-  if (!serverless) {
-    it('should warn about API export', async () => {
-      const { stdout } = await runNextCommand(['export', appDir], {
-        stdout: true,
-        stderr: true
-      })
-
-      expect(stdout).toContain('API pages are not supported in export')
-    })
-  }
-
   it('should return data on dynamic optional nested route', async () => {
     const data = await fetchViaHTTP(
       appPort,

test/integration/export/next.config.js

@@ -37,6 +37,7 @@ module.exports = phase => {
           query: { text: 'this file has an extension' }
         },
         '/query': { page: '/query', query: { a: 'blue' } },
+        // API route
         '/blog/nextjs/comment/test': { page: '/blog/[post]/comment/[id]' }
       }
     } // end exportPathMap

test/integration/export/pages/api/data.js

@@ -0,0 +1,3 @@
+export default (req, res) => {
+  res.send('Hello World')
+}

test/integration/export/test/api-routes.js

@@ -0,0 +1,28 @@
+/* eslint-env jest */
+import { join } from 'path'
+import { File, runNextCommand } from 'next-test-utils'
+
+export default function (context) {
+  describe('API routes export', () => {
+    const nextConfig = new File(join(context.appDir, 'next.config.js'))
+
+    beforeEach(() => {
+      nextConfig.replace('// API route', `'/data': { page: '/api/data' },`)
+    })
+    afterEach(() => {
+      nextConfig.restore()
+    })
+
+    it('Should throw if a route is matched', async () => {
+      const outdir = join(context.appDir, 'outApi')
+      const { stdout } = await runNextCommand(
+        ['export', context.appDir, '--outdir', outdir],
+        { stdout: true }
+      )
+
+      expect(stdout).toContain(
+        'https://err.sh/zeit/next.js/api-routes-static-export'
+      )
+    })
+  })
+}

test/integration/export/test/index.test.js

@@ -19,6 +19,7 @@ import dev from './dev'
 import { promisify } from 'util'
 import fs from 'fs'
 import dynamic from './dynamic'
+import apiRoutes from './api-routes'
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 1000 * 60 * 5
 
@@ -96,4 +97,5 @@ describe('Static Export', () => {
   browser(context)
   dev(devContext)
   dynamic(context)
+  apiRoutes(context)
 })