diff --git a/packages/primitives/src/primitives/fetch.js b/packages/primitives/src/primitives/fetch.js
index 9192c683..c15420fc 100644
--- a/packages/primitives/src/primitives/fetch.js
+++ b/packages/primitives/src/primitives/fetch.js
@@ -20,7 +20,7 @@ process.nextTick = setImmediate
 process.emitWarning = () => {}
 
 class Request extends BaseRequest {
-  constructor(input, init) {
+  constructor (input, init) {
     super(input, addDuplexToInit(init))
   }
 }
@@ -82,7 +82,7 @@ ResponseModule.Response.error = function (...args) {
  * @param {string} potentialName
  * @param {'Header.append' | 'Headers.delete' | 'Headers.get' | 'Headers.has' | 'Header.set'} errorPrefix
  */
-function normalizeAndValidateHeaderName(potentialName, errorPrefix) {
+function normalizeAndValidateHeaderName (potentialName, errorPrefix) {
   const normalizedName = potentialName.toLowerCase()
 
   if (UtilModule.isValidHeaderName(normalizedName)) {
@@ -93,7 +93,7 @@ function normalizeAndValidateHeaderName(potentialName, errorPrefix) {
   WebIDLModule.errors.invalidArgument({
     prefix: errorPrefix,
     value: normalizedName,
-    type: 'header name',
+    type: 'header name'
   })
 }
 
@@ -103,7 +103,7 @@ function normalizeAndValidateHeaderName(potentialName, errorPrefix) {
  * @param {string} potentialValue
  * @param {'Header.append' | 'Header.set'} errorPrefix
  */
-function normalizeAndValidateHeaderValue(potentialValue, errorPrefix) {
+function normalizeAndValidateHeaderValue (potentialValue, errorPrefix) {
   /**
    * To normalize a byte sequence potentialValue, remove
    * any leading and trailing HTTP whitespace bytes from
@@ -121,7 +121,7 @@ function normalizeAndValidateHeaderValue(potentialValue, errorPrefix) {
   WebIDLModule.errors.invalidArgument({
     prefix: errorPrefix,
     value: normalizedValue,
-    type: 'header value',
+    type: 'header value'
   })
 }
 
@@ -131,11 +131,11 @@ function normalizeAndValidateHeaderValue(potentialValue, errorPrefix) {
  */
 let globalDispatcher = new Agent()
 
-export function getGlobalDispatcher() {
+export function getGlobalDispatcher () {
   return globalDispatcher
 }
 
-export function setGlobalDispatcher(agent) {
+export function setGlobalDispatcher (agent) {
   if (!agent || typeof agent.dispatch !== 'function') {
     throw new InvalidArgumentError('Argument agent must implement Agent')
   }
@@ -145,11 +145,11 @@ export function setGlobalDispatcher(agent) {
 /**
  * Add `duplex: 'half'` by default to all requests
  */
-function addDuplexToInit(init) {
-  if (typeof init === 'undefined' || typeof init === 'object') {
-    return { duplex: 'half', ...init }
-  }
-  return init
+function addDuplexToInit (init) {
+  return typeof init === 'undefined' ||
+    (typeof init === 'object' && init.duplex !== 'half')
+    ? { duplex: 'half', ...init }
+    : init
 }
 
 /**
@@ -157,7 +157,7 @@ function addDuplexToInit(init) {
  * It also re-cretates a new Response object in order to allow mutations on
  * the Response headers.
  */
-export async function fetch(info, init) {
+export async function fetch (info, init) {
   init = addDuplexToInit(init)
   const res = await fetchImpl.call(getGlobalDispatcher(), info, init)
   const response = new Response(res.body, res)
diff --git a/packages/runtime/src/cli/repl.ts b/packages/runtime/src/cli/repl.ts
index 918bfdb9..64b10270 100644
--- a/packages/runtime/src/cli/repl.ts
+++ b/packages/runtime/src/cli/repl.ts
@@ -14,7 +14,7 @@ const writer: createRepl.REPLWriter = (output) => {
 }
 
 const repl = createRepl.start({ prompt: 'ƒ => ', writer })
-repl.setupHistory(join(homedir(), '.edge_runtime_repl_history'), () => { })
+repl.setupHistory(join(homedir(), '.edge_runtime_repl_history'), () => {})
 
 Object.getOwnPropertyNames(repl.context).forEach(
   (mod) => delete repl.context[mod]