fix: prevent to cache after res is written

Author: Kikobeats

src/index.js

@@ -7,7 +7,7 @@ const Keyv = require('@keyvhq/core')
 const assert = require('assert')
 const getEtag = require('etag')
 
-const { size, isFunction, hasQueryParameter, setHeaders } = require('./util')
+const { hasQueryParameter, isFunction, setHeaders, size } = require('./util')
 
 const cacheableResponse = ({
   bypassQueryParameter = 'force',
@@ -45,9 +45,10 @@ const cacheableResponse = ({
   return async opts => {
     const { req, res } = opts
     const hasForce = hasQueryParameter(req, bypassQueryParameter)
-
     const [raw, { hasValue, key, isExpired, isStale }] = await memoGet(opts)
 
+    if (res.finished) return
+
     const result = (await decompress(raw)) || {}
     const isHit = !hasForce && !isExpired && hasValue
 

test/index.js

@@ -54,6 +54,25 @@ test('compress support', async t => {
   t.is(headersOne.etag, headersTwo.etag)
 })
 
+test('exit early is get is empty', async t => {
+  let isEnd = false
+
+  const end = (res, msg) => {
+    isEnd = true
+    res.end(msg)
+  }
+
+  const url = await createServer(
+    cacheableResponse({
+      get: ({ res }) => !isEnd && end(res, 'get'),
+      send: ({ res }) => !isEnd && end(res, 'send')
+    })
+  )
+
+  const res = await got(`${url}/kikobeats`)
+  t.is(res.body, 'get')
+})
+
 test('prevent send if data is undefined', async t => {
   let isSendCalled = false
   const url = await createServer(