feat: enable cache by creating or applying

src/axios/cache.ts

@@ -1,21 +1,28 @@
-import { AxiosInstance } from 'axios';
+import Axios, { AxiosInstance, AxiosRequestConfig } from 'axios';
 import { defaultHeaderInterpreter } from '../header';
 import { applyRequestInterceptor } from '../interceptors/request';
 import { applyResponseInterceptor } from '../interceptors/response';
 import { MemoryStorage } from '../storage/memory';
 import { defaultKeyGenerator } from '../util/key-generator';
 import CacheInstance, { AxiosCacheInstance, CacheProperties } from './types';
 
-export function createCache(
+/**
+ * Apply the caching interceptors for a already created axios instance.
+ *
+ * @param axios the already created axios instance
+ * @param config the config for the caching interceptors
+ * @returns the same instance but with caching enabled
+ */
+export function applyCache(
   axios: AxiosInstance,
-  options: Partial<CacheInstance> & Partial<CacheProperties> = {}
+  config: Partial<CacheInstance> & Partial<CacheProperties> = {}
 ): AxiosCacheInstance {
   const axiosCache = axios as AxiosCacheInstance;
 
-  axiosCache.storage = options.storage || new MemoryStorage();
-  axiosCache.generateKey = options.generateKey || defaultKeyGenerator;
-  axiosCache.waiting = options.waiting || {};
-  axiosCache.headerInterpreter = options.headerInterpreter || defaultHeaderInterpreter;
+  axiosCache.storage = config.storage || new MemoryStorage();
+  axiosCache.generateKey = config.generateKey || defaultKeyGenerator;
+  axiosCache.waiting = config.waiting || {};
+  axiosCache.headerInterpreter = config.headerInterpreter || defaultHeaderInterpreter;
 
   // CacheRequestConfig values
   axiosCache.defaults = {
@@ -26,7 +33,7 @@ export function createCache(
       methods: ['get'],
       cachePredicate: { statusCheck: [200, 399] },
       update: {},
-      ...options
+      ...config
     }
   };
 
@@ -36,3 +43,17 @@ export function createCache(
 
   return axiosCache;
 }
+
+/**
+ * Returns a new axios instance with caching enabled.
+ *
+ * @param config the config for the caching interceptors
+ * @param axiosConfig the config for the created axios instance
+ * @returns the same instance but with caching enabled
+ */
+export function createCache(
+  config: Partial<CacheInstance> & Partial<CacheProperties> = {},
+  axiosConfig: AxiosRequestConfig = {}
+): AxiosCacheInstance {
+  return applyCache(Axios.create(axiosConfig), config);
+}

src/axios/types.ts

@@ -17,6 +17,10 @@ import { CachePredicate } from '../util/cache-predicate';
 import { Deferred } from '../util/deferred';
 import { KeyGenerator } from '../util/key-generator';
 
+export type CacheUpdater =
+  | ((cached: EmptyStorageValue | CachedStorageValue, newData: any) => CachedStorageValue | void)
+  | 'delete';
+
 export type DefaultCacheRequestConfig = AxiosRequestConfig & {
   cache: CacheProperties;
 };
@@ -57,22 +61,15 @@ export type CacheProperties = {
    * Once the request is resolved, this specifies what requests should we change the cache.
    * Can be used to update the request or delete other caches.
    *
-   * If the function returns void, the entry is deleted
+   * If the function returns nothing, the entry is deleted
    *
    * This is independent if the request made was cached or not.
    *
    * The id used is the same as the id on `CacheRequestConfig['id']`, auto-generated or not.
    *
    * @default {}
    */
-  update: {
-    [id: string]:
-      | 'delete'
-      | ((
-          cached: EmptyStorageValue | CachedStorageValue,
-          newData: any
-        ) => CachedStorageValue | undefined);
-  };
+  update: Record<string, CacheUpdater | undefined>;
 };
 
 /**

src/header/types.ts

@@ -7,4 +7,6 @@
  * headers was not enough to determine a valid value. Or a `number` containing
  * the number of **milliseconds** to cache the response.
  */
-export type HeaderInterpreter = (headers?: Record<string, string>) => false | undefined | number;
+export type HeaderInterpreter = (
+  headers?: Record<Lowercase<string>, string>
+) => false | undefined | number;