Introduce proper url routing for next-export which supports query strings.

lib/link.js

@@ -3,7 +3,7 @@
 import { resolve, format, parse } from 'url'
 import React, { Component, Children } from 'react'
 import PropTypes from 'prop-types'
-import Router from './router'
+import Router, { _rewriteUrlForNextExport } from './router'
 import { warn, execOnce, getLocationOrigin } from './utils'
 
 export default class Link extends Component {
@@ -126,13 +126,11 @@ export default class Link extends Component {
 
     // Add the ending slash to the paths. So, we can serve the
     // "<page>/index.html" directly.
-    const endsWithSlash = /\/$/.test(props.href)
     if (
       typeof __NEXT_DATA__ !== 'undefined' &&
-      __NEXT_DATA__.nextExport &&
+      __NEXT_DATA__.nextExport
-      !endsWithSlash
     ) {
-      props.href = `${props.href}/`
+      props.href = _rewriteUrlForNextExport(props.href)
     }
 
     return React.cloneElement(child, props)

lib/router/index.js

@@ -85,3 +85,23 @@ export function _notifyBuildIdMismatch (nextRoute) {
     window.location.href = nextRoute
   }
 }
+
+export function _rewriteUrlForNextExport (url) {
+  // If there are no query strings
+  if (!/\?/.test(url)) {
+    return rewritePath(url)
+  }
+
+  const [path, qs] = url.split('?')
+
+  const newPath = rewritePath(path)
+  return `${newPath}?${qs}`
+
+  function rewritePath (path) {
+    // If ends with slash simply return that path
+    if (/\/$/.test(path)) {
+      return path
+    }
+    return `${path}/`
+  }
+}

lib/router/router.js

@@ -5,7 +5,7 @@ import mitt from 'mitt'
 import shallowEquals from '../shallow-equals'
 import PQueue from '../p-queue'
 import { loadGetInitialProps, getURL } from '../utils'
-import { _notifyBuildIdMismatch } from './'
+import { _notifyBuildIdMismatch, _rewriteUrlForNextExport } from './'
 
 export default class Router {
   constructor (pathname, query, as, { pageLoader, Component, ErrorComponent, err } = {}) {
@@ -124,12 +124,8 @@ export default class Router {
 
     // Add the ending slash to the paths. So, we can serve the
     // "<page>/index.html" directly for the SSR page.
-    const asEndsWithSlash = /\/$/.test(as)
+    if (__NEXT_DATA__.nextExport) {
-    if (
+      as = _rewriteUrlForNextExport(as)
-      __NEXT_DATA__.nextExport &&
-      !asEndsWithSlash
-    ) {
-      as = `${as}/`
     }
 
     this.abortComponentLoad(as)