fix: don't add trailing slashes to generated routes

Module was adding a trailing slash for extra routes that
it was generating.

This isn't normally a problem as VueRouter runs by default in
non-strict mode and normalizes paths to not have trailing slashes but
when the "router.trailingSlash = false" option was set in Nuxt, then
the matching was strict and actually made trailing slashes appear in
the path.

Follow the same logic as Nuxt and:
 - don't add trailing slashes by default or when "router.trailingSlash"
   option is set to "false"
 - add trailing slashes when "router.trailingSlash" option is set
   to "true"

Resolves #717

src/helpers/routes.js

@@ -3,16 +3,17 @@ const { extractComponentOptions } = require('./components')
 const { getPageOptions, getLocaleCodes } = require('./utils')
 
 exports.makeRoutes = (baseRoutes, {
-  locales,
   defaultLocale,
-  routesNameSeparator,
   defaultLocaleRouteNameSuffix,
+  differentDomains,
   isNuxtGenerate,
-  strategy,
-  parsePages,
+  locales,
   pages,
   pagesDir,
-  differentDomains
+  parsePages,
+  routesNameSeparator,
+  strategy,
+  trailingSlash
 }) => {
   locales = getLocaleCodes(locales)
   let localizedRoutes = []
@@ -78,10 +79,12 @@ exports.makeRoutes = (baseRoutes, {
         path = componentOptions.paths[locale]
       }
 
+      const isDefaultLocale = locale === defaultLocale
+
       // For PREFIX_AND_DEFAULT strategy and default locale:
       // - if it's a parent route, add it with default locale suffix added (no suffix if route has children)
       // - if it's a child route of that extra parent route, append default suffix to it
-      if (locale === defaultLocale && strategy === STRATEGIES.PREFIX_AND_DEFAULT) {
+      if (isDefaultLocale && strategy === STRATEGIES.PREFIX_AND_DEFAULT) {
         if (!isChild) {
           const defaultRoute = { ...localizedRoute, path }
 
@@ -113,18 +116,23 @@ exports.makeRoutes = (baseRoutes, {
         // No need to add prefix if child's path is relative
         !isChildWithRelativePath &&
         // Skip default locale if strategy is PREFIX_EXCEPT_DEFAULT
-        !(locale === defaultLocale && strategy === STRATEGIES.PREFIX_EXCEPT_DEFAULT)
+        !(isDefaultLocale && strategy === STRATEGIES.PREFIX_EXCEPT_DEFAULT)
       )
 
       if (shouldAddPrefix) {
         path = `/${locale}${path}`
+      }
 
-        if (locale === defaultLocale && strategy === STRATEGIES.PREFIX && isNuxtGenerate) {
-          routes.push({
-            path: route.path,
-            redirect: path
-          })
-        }
+      // - Follow Nuxt and add or remove trailing slashes depending on "router.trailingSlash`
+      // - If "router.trailingSlash" is not specified then default to no trailing slash (like Nuxt)
+      // - Children with relative paths must not start with slash so don't append if path is empty.
+      path = path.replace(/\/+$/, '') + (trailingSlash ? '/' : '') || (isChildWithRelativePath ? '' : '/')
+
+      if (shouldAddPrefix && isDefaultLocale && strategy === STRATEGIES.PREFIX && isNuxtGenerate) {
+        routes.push({
+          path: route.path,
+          redirect: path
+        })
       }
 
       localizedRoute.path = path

src/index.js

@@ -55,6 +55,7 @@ module.exports = function (userOptions) {
 
   if (options.strategy !== STRATEGIES.NO_PREFIX) {
     if (localeCodes.length) {
+      const { trailingSlash } = this.options.router
       let isNuxtGenerate = false
       const extendRoutes = routes => {
         // This import (or more specifically 'vue-template-compiler' in helpers/components.js) needs to
@@ -65,7 +66,8 @@ module.exports = function (userOptions) {
         const localizedRoutes = makeRoutes(routes, {
           ...options,
           pagesDir,
-          isNuxtGenerate
+          isNuxtGenerate,
+          trailingSlash
         })
         routes.splice(0, routes.length)
         routes.unshift(...localizedRoutes)

src/templates/seo-head.js

@@ -66,11 +66,11 @@ function addHreflangLinks (locales, baseUrl, link) {
     localeMap.set(localeIso, locale)
   }
 
-  for (const [iso, locale] of localeMap.entries()) {
+  for (const [iso, mapLocale] of localeMap.entries()) {
     link.push({
       hid: `alternate-hreflang-${iso}`,
       rel: 'alternate',
-      href: baseUrl + this.switchLocalePath(locale.code),
+      href: baseUrl + this.switchLocalePath(mapLocale.code),
       hreflang: iso
     })
   }