From 9f992a8eb9ce67f589c3e9b56ae1d00279b3623a Mon Sep 17 00:00:00 2001
From: techcodie <bahetianshh@gmail.com>
Date: Wed, 8 Apr 2026 00:28:30 +0530
Subject: [PATCH] fix(types): align runWhen type with runtime behavior in
 InterceptorManager (#7529)
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The `runWhen` property in `AxiosInterceptorOptions` and
`AxiosInterceptorHandler` had type inconsistencies that caused
TypeScript build failures when upgrading from axios 1.13.2 to 1.13.5+.

Issues fixed:

1. `AxiosInterceptorOptions.runWhen` did not allow `null`, but
   `InterceptorManager.use()` explicitly sets it to `null` when no
   options are provided (`runWhen: options ? options.runWhen : null`).

2. `AxiosInterceptorHandler.runWhen` used `AxiosRequestConfig` instead
   of `InternalAxiosRequestConfig`, creating a type mismatch with
   `AxiosInterceptorOptions` which uses `InternalAxiosRequestConfig`.

3. In `index.d.ts`, the `AxiosInterceptorHandler.runWhen` type was
   `(config: AxiosRequestConfig) => boolean | null` — the `| null`
   was incorrectly placed as part of the return type rather than making
   the entire function type nullable.

4. `AxiosInterceptorHandler.runWhen` is now optional (`?`) to also
   allow `undefined`, matching the runtime case where options are
   passed without a `runWhen` property (i.e. `options.runWhen` is
   `undefined`).

Fixes #7404

Co-authored-by: Jay <jasonsaayman@gmail.com>
---
 index.d.cts | 4 ++--
 index.d.ts  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/index.d.cts b/index.d.cts
index 918cb08f..c386ae82 100644
--- a/index.d.cts
+++ b/index.d.cts
@@ -629,7 +629,7 @@ declare namespace axios {
 
   interface AxiosInterceptorOptions {
     synchronous?: boolean;
-    runWhen?: (config: InternalAxiosRequestConfig) => boolean;
+    runWhen?: ((config: InternalAxiosRequestConfig) => boolean) | null;
   }
 
   type AxiosInterceptorFulfilled<T> = (value: T) => T | Promise<T>;
@@ -650,7 +650,7 @@ declare namespace axios {
     fulfilled: AxiosInterceptorFulfilled<T>;
     rejected?: AxiosInterceptorRejected;
     synchronous: boolean;
-    runWhen?: (config: AxiosRequestConfig) => boolean;
+    runWhen?: ((config: InternalAxiosRequestConfig) => boolean) | null;
   }
 
   interface AxiosInterceptorManager<V> {
diff --git a/index.d.ts b/index.d.ts
index 300eb7c5..af25bd44 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -639,7 +639,7 @@ export interface CancelTokenSource {
 
 export interface AxiosInterceptorOptions {
   synchronous?: boolean;
-  runWhen?: (config: InternalAxiosRequestConfig) => boolean;
+  runWhen?: ((config: InternalAxiosRequestConfig) => boolean) | null;
 }
 
 type AxiosInterceptorFulfilled<T> = (value: T) => T | Promise<T>;
@@ -660,7 +660,7 @@ interface AxiosInterceptorHandler<T> {
   fulfilled: AxiosInterceptorFulfilled<T>;
   rejected?: AxiosInterceptorRejected;
   synchronous: boolean;
-  runWhen: (config: AxiosRequestConfig) => boolean | null;
+  runWhen?: ((config: InternalAxiosRequestConfig) => boolean) | null;
 }
 
 export interface AxiosInterceptorManager<V> {