From be16d1e6268f16afd686352b669ea8825b1c2f93 Mon Sep 17 00:00:00 2001
From: Jane Manchun Wong <jane@wongmjane.com>
Date: Sun, 29 Mar 2020 00:43:07 +0800
Subject: [PATCH 1/3] Generic Type for GetStaticPaths

---
 packages/next/types/index.d.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/next/types/index.d.ts b/packages/next/types/index.d.ts
index 271e1b532d278..6a4c53d78c1f0 100644
--- a/packages/next/types/index.d.ts
+++ b/packages/next/types/index.d.ts
@@ -78,8 +78,10 @@ export type GetStaticProps<
   revalidate?: number | boolean
 }>
 
-export type GetStaticPaths = () => Promise<{
-  paths: Array<string | { params: ParsedUrlQuery }>
+export type GetStaticPaths<
+  P extends ParsedUrlQuery = ParsedUrlQuery
+> = () => Promise<{
+  paths: Array<string | { params: P }>
   fallback: boolean
 }>
 

From 735ee6f96cb5ed1b72fd27a00c3a80b6c3d32e20 Mon Sep 17 00:00:00 2001
From: Jane Manchun Wong <jane@wongmjane.com>
Date: Sun, 29 Mar 2020 01:31:44 +0800
Subject: [PATCH 2/3] Add generic typing for params to GSSP and GSP too

---
 packages/next/types/index.d.ts | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/packages/next/types/index.d.ts b/packages/next/types/index.d.ts
index 6a4c53d78c1f0..6091f716b65c5 100644
--- a/packages/next/types/index.d.ts
+++ b/packages/next/types/index.d.ts
@@ -67,9 +67,10 @@ export {
 }
 
 export type GetStaticProps<
-  P extends { [key: string]: any } = { [key: string]: any }
+  P extends { [key: string]: any } = { [key: string]: any },
+  Q extends ParsedUrlQuery = ParsedUrlQuery
 > = (ctx: {
-  params?: ParsedUrlQuery
+  params?: Q
   preview?: boolean
   previewData?: any
   env: Env
@@ -86,11 +87,12 @@ export type GetStaticPaths<
 }>
 
 export type GetServerSideProps<
-  P extends { [key: string]: any } = { [key: string]: any }
+  P extends { [key: string]: any } = { [key: string]: any },
+  Q extends ParsedUrlQuery = ParsedUrlQuery
 > = (context: {
   req: IncomingMessage
   res: ServerResponse
-  params?: ParsedUrlQuery
+  params?: Q
   query: ParsedUrlQuery
   env: Env
   preview?: boolean

From db3038bb8f10204deccd0ef72bf48f159003ba64 Mon Sep 17 00:00:00 2001
From: Luis Alvarez <luis@zeit.co>
Date: Mon, 30 Mar 2020 21:31:32 -0500
Subject: [PATCH 3/3] Added basic tests

---
 .../typescript/pages/ssg/[slug].tsx           | 29 +++++++++++++++++++
 .../typescript/pages/ssr/[slug].tsx           | 21 ++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 test/integration/typescript/pages/ssg/[slug].tsx
 create mode 100644 test/integration/typescript/pages/ssr/[slug].tsx

diff --git a/test/integration/typescript/pages/ssg/[slug].tsx b/test/integration/typescript/pages/ssg/[slug].tsx
new file mode 100644
index 0000000000000..5d6af8cfcc780
--- /dev/null
+++ b/test/integration/typescript/pages/ssg/[slug].tsx
@@ -0,0 +1,29 @@
+import { GetStaticPaths, GetStaticProps } from 'next'
+
+type Params = {
+  slug: string
+}
+
+type Props = {
+  data: string
+}
+
+export const getStaticPaths: GetStaticPaths<Params> = async () => {
+  return {
+    paths: [{ params: { slug: 'test' } }],
+    fallback: false,
+  }
+}
+
+export const getStaticProps: GetStaticProps<Props, Params> = async ({
+  params,
+}) => {
+  return {
+    props: { data: params!.slug },
+    revalidate: false,
+  }
+}
+
+export default function Page({ data }: Props) {
+  return <h1>{data}</h1>
+}
diff --git a/test/integration/typescript/pages/ssr/[slug].tsx b/test/integration/typescript/pages/ssr/[slug].tsx
new file mode 100644
index 0000000000000..ac201cbf1984a
--- /dev/null
+++ b/test/integration/typescript/pages/ssr/[slug].tsx
@@ -0,0 +1,21 @@
+import { GetServerSideProps } from 'next'
+
+type Params = {
+  slug: string
+}
+
+type Props = {
+  data: string
+}
+
+export const getServerSideProps: GetServerSideProps<Props, Params> = async ({
+  params,
+}) => {
+  return {
+    props: { data: params!.slug },
+  }
+}
+
+export default function Page({ data }: Props) {
+  return <h1>{data}</h1>
+}