From a5eb6895de26403ed704a54ec10da1b92d38f3b0 Mon Sep 17 00:00:00 2001
From: Remco Haszing <remcohaszing@gmail.com>
Date: Sun, 7 Jun 2020 14:46:25 +0200
Subject: [PATCH] Make the default type of response data never
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This requires TypeScript users to explicitly define the type of the data they
are consuming.

Before this, data was `any` by default. This means TypeScript consumers didn’t
get type safety if they forgot to specify the type.

Technically this is a breaking change for TypeScript users, as this will report
errors if they forgot to specifiy the response type. The simplest workaround
would be to explicitly set the response type to `any`, so it’s not breaking
much.

The `unknown` type is probably a slightly better fit, but this requires
TypeScript ^3.

`data` is still `any` in the very specific use case mentioned in
https://github.com/microsoft/TypeScript/issues/38969
---
 index.d.ts               | 22 +++++++++++-----------
 test/typescript/axios.ts |  2 +-
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index 74b2acd2cc..088e48cd7c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -73,7 +73,7 @@ export interface AxiosRequestConfig {
   decompress?: boolean;
 }
 
-export interface AxiosResponse<T = any>  {
+export interface AxiosResponse<T = never>  {
   data: T;
   status: number;
   statusText: string;
@@ -82,7 +82,7 @@ export interface AxiosResponse<T = any>  {
   request?: any;
 }
 
-export interface AxiosError<T = any> extends Error {
+export interface AxiosError<T = never> extends Error {
   config: AxiosRequestConfig;
   code?: string;
   request?: any;
@@ -91,7 +91,7 @@ export interface AxiosError<T = any> extends Error {
   toJSON: () => object;
 }
 
-export interface AxiosPromise<T = any> extends Promise<AxiosResponse<T>> {
+export interface AxiosPromise<T = never> extends Promise<AxiosResponse<T>> {
 }
 
 export interface CancelStatic {
@@ -136,14 +136,14 @@ export interface AxiosInstance {
     response: AxiosInterceptorManager<AxiosResponse>;
   };
   getUri(config?: AxiosRequestConfig): string;
-  request<T = any, R = AxiosResponse<T>> (config: AxiosRequestConfig): Promise<R>;
-  get<T = any, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
-  delete<T = any, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
-  head<T = any, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
-  options<T = any, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
-  post<T = any, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
-  put<T = any, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
-  patch<T = any, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
+  request<T = never, R = AxiosResponse<T>> (config: AxiosRequestConfig): Promise<R>;
+  get<T = never, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
+  delete<T = never, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
+  head<T = never, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
+  options<T = never, R = AxiosResponse<T>>(url: string, config?: AxiosRequestConfig): Promise<R>;
+  post<T = never, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
+  put<T = never, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
+  patch<T = never, R = AxiosResponse<T>>(url: string, data?: any, config?: AxiosRequestConfig): Promise<R>;
 }
 
 export interface AxiosStatic extends AxiosInstance {
diff --git a/test/typescript/axios.ts b/test/typescript/axios.ts
index c584dfc578..1984a23ba9 100644
--- a/test/typescript/axios.ts
+++ b/test/typescript/axios.ts
@@ -284,7 +284,7 @@ axios.interceptors.response.use((response: AxiosResponse) => Promise.resolve(res
 // Adapters
 
 const adapter: AxiosAdapter = (config: AxiosRequestConfig) => {
-  const response: AxiosResponse = {
+  const response: AxiosResponse<any> = {
     data: { foo: 'bar' },
     status: 200,
     statusText: 'OK',