feat: added isAxiosCacheInterceptor function

src/cache/create.ts

@@ -9,6 +9,8 @@ import type { CacheInstance, CacheProperties } from './cache';
 
 export type CacheOptions = Partial<CacheInstance> & Partial<CacheProperties>;
 
+const symbolKey = Symbol();
+
 /**
  * Apply the caching interceptors for a already created axios instance.
  *
@@ -87,6 +89,9 @@ export function setupCache(
   axiosCache.requestInterceptor.use();
   axiosCache.responseInterceptor.use();
 
+  // @ts-expect-error - internal only
+  axiosCache[symbolKey] = 1;
+
   return axiosCache;
 }
 
@@ -94,3 +99,13 @@ export function setupCache(
 export const useCache = setupCache as unknown as 'use setupCache instead';
 /** @deprecated */
 export const createCache = setupCache as unknown as 'use setupCache instead';
+
+/**
+ * Detects if the given parameter has caching enabled. The only way to this return true is
+ * by using the {@link setupCache} function.
+ *
+ * @param axios The axios instance to use
+ * @returns True if the axios instance is using the caching interceptor
+ */
+export const isAxiosCacheInterceptor = (axios: any): axios is AxiosCacheInstance =>
+  !!axios && !!axios[symbolKey];

src/index.browser.ts

@@ -1,6 +1,11 @@
 /** Index file for webpack and cdn usage */
 
-export { createCache, setupCache, useCache } from './cache/create';
+export {
+  createCache,
+  isAxiosCacheInterceptor,
+  setupCache,
+  useCache
+} from './cache/create';
 export { BrowserAxiosStorage } from './storage/browser';
 export { MemoryAxiosStorage } from './storage/memory';
 export { AxiosStorage } from './storage/storage';

src/index.development.ts

@@ -1,6 +1,11 @@
 /** Index file for webpack and cdn usage */
 
-export { createCache, setupCache, useCache } from './cache/create';
+export {
+  createCache,
+  isAxiosCacheInterceptor,
+  setupCache,
+  useCache
+} from './cache/create';
 export { BrowserAxiosStorage } from './storage/browser';
 export { MemoryAxiosStorage } from './storage/memory';
 export { AxiosStorage } from './storage/storage';

test/bundle.test.ts

@@ -1,4 +1,4 @@
-import { setupCache } from '../src/cache/create';
+import { isAxiosCacheInterceptor, setupCache } from '../src/cache/create';
 import { BrowserAxiosStorage } from '../src/storage/browser';
 import { MemoryAxiosStorage } from '../src/storage/memory';
 import { AxiosStorage } from '../src/storage/storage';
@@ -8,6 +8,7 @@ describe('test bundle imports', () => {
     const bundle = await import('../src/index.browser');
 
     expect(bundle.setupCache).toBe(setupCache);
+    expect(bundle.isAxiosCacheInterceptor).toBe(isAxiosCacheInterceptor);
     expect(bundle.AxiosStorage).toBe(AxiosStorage);
     expect(bundle.BrowserAxiosStorage).toBe(BrowserAxiosStorage);
     expect(bundle.MemoryAxiosStorage).toBe(MemoryAxiosStorage);
@@ -22,6 +23,7 @@ describe('test bundle imports', () => {
     expect(console.warn).toHaveBeenCalledTimes(1);
 
     expect(bundle.setupCache).toBe(setupCache);
+    expect(bundle.isAxiosCacheInterceptor).toBe(isAxiosCacheInterceptor);
     expect(bundle.AxiosStorage).toBe(AxiosStorage);
     expect(bundle.BrowserAxiosStorage).toBe(BrowserAxiosStorage);
     expect(bundle.MemoryAxiosStorage).toBe(MemoryAxiosStorage);

test/cache/create.test.ts

@@ -1,5 +1,5 @@
 import Axios from 'axios';
-import { setupCache } from '../../src/cache/create';
+import { isAxiosCacheInterceptor, setupCache } from '../../src/cache/create';
 
 describe('tests header interpreter', () => {
   it('tests argument composition', () => {
@@ -11,4 +11,18 @@ describe('tests header interpreter', () => {
     expect(withConfig).not.toBeUndefined();
     expect(withConfig.defaults.cache.ttl).toBe(1234);
   });
+
+  it('tests isAxiosCacheInterceptor', () => {
+    expect(isAxiosCacheInterceptor(void 0)).toBe(false);
+    expect(isAxiosCacheInterceptor(1)).toBe(false);
+    expect(isAxiosCacheInterceptor('a')).toBe(false);
+    expect(isAxiosCacheInterceptor({})).toBe(false);
+    expect(isAxiosCacheInterceptor(Axios)).toBe(false);
+    expect(isAxiosCacheInterceptor(() => 0)).toBe(false);
+    expect(isAxiosCacheInterceptor(null)).toBe(false);
+    expect(isAxiosCacheInterceptor(undefined)).toBe(false);
+    expect(isAxiosCacheInterceptor({ a: 1, b: 'a' })).toBe(false);
+
+    expect(isAxiosCacheInterceptor(setupCache(Axios.create()))).toBe(true);
+  });
 });