Use jsonPageRes instead of xhr (#1424)

examples/with-flow/types/next.js.flow

@@ -42,7 +42,7 @@ declare module "next/document" {
   declare export var Main: Class<React$Component<void, any, any>>;
   declare export var NextScript: Class<React$Component<void, any, any>>;
   declare export default Class<React$Component<void, any, any>> & {
-    getInitialProps: (ctx: {pathname: string, query: any, req?: any, res?: any, xhr?: any, err?: any}) => Promise<any>;
+    getInitialProps: (ctx: {pathname: string, query: any, req?: any, res?: any, jsonPageRes?: any, err?: any}) => Promise<any>;
     renderPage(cb: Function): void;
   };
 }

lib/error.js

@@ -3,8 +3,8 @@ import HTTPStatus from 'http-status'
 import Head from './head'
 
 export default class Error extends React.Component {
-  static getInitialProps ({ res, xhr }) {
-    const statusCode = res ? res.statusCode : (xhr ? xhr.status : null)
+  static getInitialProps ({ res, jsonPageRes }) {
+    const statusCode = res ? res.statusCode : (jsonPageRes ? jsonPageRes.status : null)
     return { statusCode }
   }
 

lib/router/router.js

@@ -341,7 +341,7 @@ export default class Router {
 
     const res = await promise
     // We need to clone this to prevent reading the body twice
-    // Becuase it's possible only once to read res.json() or a similar method.
+    // Because it's possible only once to read res.json() or a similar method.
     return res.clone()
   }
 

readme.md

@@ -223,7 +223,7 @@ _Note: `getInitialProps` can **not** be used in children components. Only in `pa
 - `query` - query string section of URL parsed as an object
 - `req` - HTTP request object (server only)
 - `res` - HTTP response object (server only)
-- `xhr` - XMLHttpRequest object (client only)
+- `jsonPageRes` - [Fetch Response](https://developer.mozilla.org/en-US/docs/Web/API/Response) object (client only)
 - `err` - Error object if any error is encountered during the rendering
 
 ### Routing
@@ -602,8 +602,8 @@ The `ctx` object is equivalent to the one received in all [`getInitialProps`](#f
 ```jsx
 import React from 'react'
 export default class Error extends React.Component {
-  static getInitialProps ({ res, xhr }) {
-    const statusCode = res ? res.statusCode : (xhr ? xhr.status : null)
+  static getInitialProps ({ res, jsonPageRes }) {
+    const statusCode = res ? res.statusCode : (jsonPageRes ? jsonPageRes.status : null)
     return { statusCode }
   }