diff --git a/lib/_tls_common.js b/lib/_tls_common.js
index e4180a2f4dc7a3..9f7747c1b52848 100644
--- a/lib/_tls_common.js
+++ b/lib/_tls_common.js
@@ -100,15 +100,12 @@ exports.createSecureContext = function createSecureContext(options) {
 
   const c = new SecureContext(options.secureProtocol, secureOptions,
                               options.minVersion, options.maxVersion);
-  let i;
-  let val;
 
   // Add CA before the cert to be able to load cert's issuer in C++ code.
   const { ca } = options;
   if (ca) {
     if (ArrayIsArray(ca)) {
-      for (i = 0; i < ca.length; ++i) {
-        val = ca[i];
+      for (const val of ca) {
         validateKeyOrCertOption('ca', val);
         c.context.addCACert(val);
       }
@@ -123,8 +120,7 @@ exports.createSecureContext = function createSecureContext(options) {
   const { cert } = options;
   if (cert) {
     if (ArrayIsArray(cert)) {
-      for (i = 0; i < cert.length; ++i) {
-        val = cert[i];
+      for (const val of cert) {
         validateKeyOrCertOption('cert', val);
         c.context.setCert(val);
       }
@@ -142,8 +138,7 @@ exports.createSecureContext = function createSecureContext(options) {
   const passphrase = options.passphrase;
   if (key) {
     if (ArrayIsArray(key)) {
-      for (i = 0; i < key.length; ++i) {
-        val = key[i];
+      for (const val of key) {
         // eslint-disable-next-line eqeqeq
         const pem = (val != undefined && val.pem !== undefined ? val.pem : val);
         validateKeyOrCertOption('key', pem);
@@ -242,8 +237,8 @@ exports.createSecureContext = function createSecureContext(options) {
 
   if (options.crl) {
     if (ArrayIsArray(options.crl)) {
-      for (i = 0; i < options.crl.length; i++) {
-        c.context.addCRL(options.crl[i]);
+      for (const crl of options.crl) {
+        c.context.addCRL(crl);
       }
     } else {
       c.context.addCRL(options.crl);
@@ -259,8 +254,7 @@ exports.createSecureContext = function createSecureContext(options) {
       toBuf = require('internal/crypto/util').toBuf;
 
     if (ArrayIsArray(options.pfx)) {
-      for (i = 0; i < options.pfx.length; i++) {
-        const pfx = options.pfx[i];
+      for (const pfx of options.pfx) {
         const raw = pfx.buf ? pfx.buf : pfx;
         const buf = toBuf(raw);
         const passphrase = pfx.passphrase || options.passphrase;
diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
index f8c462ddd281c1..0207d9bfd6c152 100644
--- a/lib/_tls_wrap.js
+++ b/lib/_tls_wrap.js
@@ -530,9 +530,9 @@ function makeMethodProxy(name) {
       return this._parent[name].apply(this._parent, args);
   };
 }
-for (let n = 0; n < proxiedMethods.length; n++) {
-  tls_wrap.TLSWrap.prototype[proxiedMethods[n]] =
-    makeMethodProxy(proxiedMethods[n]);
+for (const proxiedMethod of proxiedMethods) {
+  tls_wrap.TLSWrap.prototype[proxiedMethod] =
+    makeMethodProxy(proxiedMethod);
 }
 
 tls_wrap.TLSWrap.prototype.close = function close(cb) {
@@ -1412,8 +1412,7 @@ Server.prototype[EE.captureRejectionSymbol] = function(
 function SNICallback(servername, callback) {
   const contexts = this.server._contexts;
 
-  for (let i = 0; i < contexts.length; i++) {
-    const elem = contexts[i];
+  for (const elem of contexts) {
     if (elem[0].test(servername)) {
       callback(null, elem[1]);
       return;
diff --git a/lib/internal/tls.js b/lib/internal/tls.js
index d7370ad52c0f8e..8d538b27574402 100644
--- a/lib/internal/tls.js
+++ b/lib/internal/tls.js
@@ -9,12 +9,11 @@ const {
 // C=US\nST=CA\nL=SF\nO=Joyent\nOU=Node.js\nCN=ca1\nemailAddress=ry@clouds.org
 function parseCertString(s) {
   const out = ObjectCreate(null);
-  const parts = s.split('\n');
-  for (let i = 0, len = parts.length; i < len; i++) {
-    const sepIndex = parts[i].indexOf('=');
+  for (const part of s.split('\n')) {
+    const sepIndex = part.indexOf('=');
     if (sepIndex > 0) {
-      const key = parts[i].slice(0, sepIndex);
-      const value = parts[i].slice(sepIndex + 1);
+      const key = part.slice(0, sepIndex);
+      const value = part.slice(sepIndex + 1);
       if (key in out) {
         if (!ArrayIsArray(out[key])) {
           out[key] = [out[key]];