feat(cache): export cache deletion functionality (#40)

index.js

@@ -42,9 +42,22 @@ cachingFetch.defaults = function (_uri, _opts) {
   }
 
   defaultedFetch.defaults = fetch.defaults
+  defaultedFetch.delete = fetch.delete
   return defaultedFetch
 }
 
+cachingFetch.delete = cacheDelete
+function cacheDelete (uri, opts) {
+  opts = configureOptions(opts)
+  if (opts.cacheManager) {
+    const req = new fetch.Request(uri, {
+      method: opts.method,
+      headers: opts.headers
+    })
+    return opts.cacheManager.delete(req, opts)
+  }
+}
+
 function initializeCache (opts) {
   if (typeof opts.cacheManager === 'string') {
     if (!Cache) {

test/cache.js

@@ -100,6 +100,39 @@ test('nothing cached if body stream never used', t => {
   })
 })
 
+test('exports cache deletion API', t => {
+  tnock(t, HOST).get('/test').twice().reply(200, CONTENT, HEADERS)
+  return fetch(`${HOST}/test`, {
+    cacheManager: CACHE,
+    retry: {retries: 0}
+  }).then(res => {
+    t.notOk(
+      res.headers.get('x-local-cache'),
+      'no cache headers if response is from network'
+    )
+    return res.buffer()
+  }).then(body => {
+    t.deepEqual(body, CONTENT, 'got remote content')
+    return fetch.delete(`${HOST}/test`, {
+      cacheManager: CACHE
+    })
+  }).then(() => {
+    return fetch(`${HOST}/test`, {
+      cacheManager: CACHE,
+      retry: {retries: 0}
+    })
+  }).then(res => {
+    t.equal(res.status, 200, 'request succeeded')
+    t.notOk(
+      res.headers.get('x-local-cache'),
+      'no cache headers if response is from network'
+    )
+    return res.buffer()
+  }).then(body => {
+    t.deepEqual(body, CONTENT, 'got remote content')
+  })
+})
+
 test('small responses cached', t => {
   tnock(t, HOST).get('/test').reply(200, CONTENT, {
     'Content-Length': CONTENT.length,