Fixing instance.defaults.headers type (#4557)

* Fixing instance.defaults.headers type

* remove console.log()

Co-authored-by: Jay <jasonsaayman@gmail.com>

index.d.ts

@@ -241,6 +241,12 @@ export class Axios {
 export interface AxiosInstance extends Axios {
   (config: AxiosRequestConfig): AxiosPromise;
   (url: string, config?: AxiosRequestConfig): AxiosPromise;
+
+  defaults: Omit<AxiosDefaults, 'headers'> & {
+    headers: HeadersDefaults & {
+      [key: string]: string | number | boolean | undefined
+    }
+  };
 }
 
 export interface GenericFormData {

test/typescript/axios.ts

@@ -251,6 +251,8 @@ instance1.post('/user', { foo: 'bar' }, { headers: { 'X-FOO': 'bar' } })
 
 // Defaults
 
+axios.defaults.headers['X-FOO'];
+
 axios.defaults.baseURL = 'https://api.example.com/';
 axios.defaults.headers.common['Authorization'] = 'token';
 axios.defaults.headers.post['X-FOO'] = 'bar';