fix

lib/interceptor/cache.js

@@ -9,20 +9,26 @@ const { assertCacheStore, assertCacheMethods } = require('../util/cache.js')
 const AGE_HEADER = Buffer.from('age')
 
 /**
- * @param {import('../../types/cache-interceptor.d.ts').default.CacheOptions} [globalOpts]
+ * @param {import('../../types/cache-interceptor.d.ts').default.CacheOptions} [opts]
  * @returns {import('../../types/dispatcher.d.ts').default.DispatcherComposeInterceptor}
  */
-module.exports = (globalOpts = {}) => {
+module.exports = (opts = {}) => {
   const {
     store = new MemoryCacheStore(),
     methods = ['GET']
-  } = globalOpts
+  } = opts
 
-  assertCacheStore(store)
-  assertCacheMethods(methods)
+  if (typeof opts !== 'object' || opts === null) {
+    throw new TypeError(`expected type of opts to be an Object, got ${store === null ? 'null' : typeof store}`)
+  }
+
+  assertCacheStore(store, 'opts.store')
+  assertCacheMethods(methods, 'opts.methods')
 
-  globalOpts.store = store
-  globalOpts.methods = methods
+  const globalOpts = {
+    store,
+    methods
+  }
 
   return dispatch => {
     return (opts, handler) => {

lib/util/cache.js

@@ -181,33 +181,37 @@ function parseVaryHeader (varyHeader, headers) {
  * @param {unknown} store
  * @returns {asserts store is import('../../types/cache-interceptor.d.ts').default.CacheStore}
  */
-function assertCacheStore (store) {
+function assertCacheStore (store, name = 'CacheStore') {
   if (typeof store !== 'object' || store === null) {
-    throw new TypeError(`expected type to be an store, got ${typeof store}`)
+    throw new TypeError(`expected type of ${name} to be a CacheStore, got ${store === null ? 'null' : typeof store}`)
   }
 
   for (const fn of ['createReadStream', 'createWriteStream', 'deleteByOrigin']) {
     if (typeof store[fn] !== 'function') {
-      throw new TypeError(`CacheStore needs a \`${fn}()\` function`)
+      throw new TypeError(`${name} needs to have a \`${fn}()\` function`)
     }
   }
 
   if (typeof store.isFull !== 'boolean') {
-    throw new TypeError(`CacheStore needs a isFull getter with type boolean, current type: ${typeof store.isFull}`)
+    throw new TypeError(`${name} needs a isFull getter with type boolean, current type: ${typeof store.isFull}`)
   }
 }
 /**
  * @param {unknown} methods
  * @returns {asserts methods is import('../../types/cache-interceptor.d.ts').default.CacheMethods[]}
  */
-function assertCacheMethods (methods) {
+function assertCacheMethods (methods, name = 'CacheMethods') {
   if (!Array.isArray(methods)) {
-    throw new TypeError(`expected type to be an array, got ${typeof methods}`)
+    throw new TypeError(`expected type of ${name} needs to be an array, got ${methods === null ? 'null' : typeof methods}`)
+  }
+
+  if (methods.length === 0) {
+    throw new TypeError(`${name} needs to have at least one method`)
   }
 
   for (const method of methods) {
     if (!safeHTTPMethods.includes(method)) {
-      throw new TypeError(`CacheMethods needs to be one of ${safeHTTPMethods.join(', ')}, got ${method}`)
+      throw new TypeError(`element of ${name}-array needs to be one of following values: ${safeHTTPMethods.join(', ')}, got ${method}`)
     }
   }
 }