Inject lang into getStaticProps and company

__tests__/builder.test.js

@@ -74,5 +74,25 @@ describe('builder', () => {
       expect(pages.toString()).toContain('I18nProvider')
       expect(pages.toString()).toContain('Page = Object.assign(Page, { ...C })')
     })
+
+    test('Should inject lang to getStaticProps', () => {
+      const deflt = fs.readFileSync('examples/static-site/pages/index.js')
+      const es = fs.readFileSync('examples/static-site/pages/es/index.js')
+      const ca = fs.readFileSync('examples/static-site/pages/ca/index.js')
+      const en = fs.readFileSync('examples/static-site/pages/en/index.js')
+
+      expect(deflt.toString()).toContain(
+        `export const getStaticProps = ctx => _rest.getStaticProps({ ...ctx, lang: 'en' })`
+      )
+      expect(es.toString()).toContain(
+        `export const getStaticProps = ctx => _rest.getStaticProps({ ...ctx, lang: 'es' })`
+      )
+      expect(ca.toString()).toContain(
+        `export const getStaticProps = ctx => _rest.getStaticProps({ ...ctx, lang: 'ca' })`
+      )
+      expect(en.toString()).toContain(
+        `export const getStaticProps = ctx => _rest.getStaticProps({ ...ctx, lang: 'en' })`
+      )
+    })
   })
 })

cli/builder.js

@@ -74,14 +74,35 @@ function readPageNamespaces(langs) {
   })
 }
 
+function hasSpecialMethod(data, name) {
+  return data.match(new RegExp(`export (const|var|let|function) ${name}`))
+}
+
+function specialMethod(name, lang) {
+  return `export const ${name} = ctx => _rest.${name}({ ...ctx, lang: '${lang}' })`
+}
+
 /**
  * STEP 3: Build page in each lang path
  */
 function getPageTemplate(prefix, page, lang, namespaces) {
+  const clearCommentsRgx = /\/\*[\s\S]*?\*\/|\/\/.*/g
+  const pageData = fs
+    .readFileSync(page)
+    .toString('UTF-8')
+    .replace(clearCommentsRgx, '')
+  const isGetStaticProps = hasSpecialMethod(pageData, 'getStaticProps')
+  const isGetStaticPaths = hasSpecialMethod(pageData, 'getStaticPaths')
+  const isGetServerSideProps = hasSpecialMethod(pageData, 'getServerSideProps')
+  const hasSomeSpecialMethod =
+    isGetStaticProps || isGetStaticPaths || isGetServerSideProps
+
   return `// @ts-nocheck
 import I18nProvider from 'next-translate/I18nProvider'
 import React from 'react'
-import C from '${prefix}/${clearPageExt(page)}'
+import C${
+    hasSomeSpecialMethod ? ', * as _rest' : ''
+  } from '${prefix}/${clearPageExt(page)}'
 ${namespaces
   .map(
     (ns, i) =>
@@ -103,6 +124,10 @@ export default function Page(p){
 
 Page = Object.assign(Page, { ...C })
 
+${isGetStaticProps ? specialMethod('getStaticProps', lang) : ''}
+${isGetStaticPaths ? specialMethod('getStaticPaths', lang) : ''}
+${isGetServerSideProps ? specialMethod('getServerSideProps', lang) : ''}
+
 export * from '${prefix}/${clearPageExt(page)}'
 `
 }

examples/static-site/pages_/index.tsx

@@ -10,7 +10,7 @@ import Header from '../components/header'
 
 // @ts-ignore
 export default function Home(props) {
-  const { t, lang } = useTranslation()
+  const { t } = useTranslation()
   const description = t('home:description')
   const linkName = t('home:more-examples')
 
@@ -27,6 +27,7 @@ export default function Home(props) {
   )
 }
 
-export const getStaticProps = async () => ({
-  props: { getStaticPropsWorks: true },
+// @ts-ignore
+export const getStaticProps = async ({ lang }) => ({
+  props: { getStaticPropsWorks: true, lang },
 })

package.json

@@ -1,6 +1,6 @@
 {
   "name": "next-translate",
-  "version": "0.12.0",
+  "version": "0.13.0-canary.1",
   "description": "Next.js utility to translate pages without the need of a server (static i18n pages generator).",
   "license": "MIT",
   "keywords": [
@@ -49,7 +49,7 @@
     "husky": "4.2.3",
     "jest": "25.1.0",
     "next": "9.3.1",
-    "prettier": "1.19.1",
+    "prettier": "2.0.2",
     "pretty-quick": "2.0.1",
     "react": "16.13.1",
     "react-dom": "16.13.1",