diff --git a/src/scripts/android/updateAndroidManifest.js b/src/scripts/android/updateAndroidManifest.js
index 0b6538ae..9bd751a1 100644
--- a/src/scripts/android/updateAndroidManifest.js
+++ b/src/scripts/android/updateAndroidManifest.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/hooks/afterPrepare.js b/src/scripts/hooks/afterPrepare.js
index babf6df3..b78aa5a2 100644
--- a/src/scripts/hooks/afterPrepare.js
+++ b/src/scripts/hooks/afterPrepare.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/hooks/beforePluginInstall.js b/src/scripts/hooks/beforePluginInstall.js
index 0a16dfd0..bee2323c 100644
--- a/src/scripts/hooks/beforePluginInstall.js
+++ b/src/scripts/hooks/beforePluginInstall.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/hooks/beforePrepare.js b/src/scripts/hooks/beforePrepare.js
index 91027b13..6d7c2553 100644
--- a/src/scripts/hooks/beforePrepare.js
+++ b/src/scripts/hooks/beforePrepare.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/ios/enableEntitlements.js b/src/scripts/ios/enableEntitlements.js
index db48f9f7..91dc4062 100644
--- a/src/scripts/ios/enableEntitlements.js
+++ b/src/scripts/ios/enableEntitlements.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/ios/updateAssociatedDomains.js b/src/scripts/ios/updateAssociatedDomains.js
index f921a819..b5242eb5 100644
--- a/src/scripts/ios/updateAssociatedDomains.js
+++ b/src/scripts/ios/updateAssociatedDomains.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/ios/updateDevelopmentTeam.js b/src/scripts/ios/updateDevelopmentTeam.js
index edcc9634..28f09d68 100644
--- a/src/scripts/ios/updateDevelopmentTeam.js
+++ b/src/scripts/ios/updateDevelopmentTeam.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/ios/updatePlist.js b/src/scripts/ios/updatePlist.js
index 27ce828c..5d64b6ca 100644
--- a/src/scripts/ios/updatePlist.js
+++ b/src/scripts/ios/updatePlist.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/lib/fileHelper.js b/src/scripts/lib/fileHelper.js
index 73c06c3c..6ba50c3e 100644
--- a/src/scripts/lib/fileHelper.js
+++ b/src/scripts/lib/fileHelper.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/lib/xmlHelper.js b/src/scripts/lib/xmlHelper.js
index 2a3b8f9b..364dc719 100644
--- a/src/scripts/lib/xmlHelper.js
+++ b/src/scripts/lib/xmlHelper.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/npm/downloadNpmDependencies.js b/src/scripts/npm/downloadNpmDependencies.js
index f4f8d54c..ee5eebb7 100644
--- a/src/scripts/npm/downloadNpmDependencies.js
+++ b/src/scripts/npm/downloadNpmDependencies.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/npm/processConfigXml.js b/src/scripts/npm/processConfigXml.js
index 382cc6c1..9ae54a40 100644
--- a/src/scripts/npm/processConfigXml.js
+++ b/src/scripts/npm/processConfigXml.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties
 
diff --git a/src/scripts/npm/updateChangeLog.js b/src/scripts/npm/updateChangeLog.js
index 03bd24f1..7584994c 100644
--- a/src/scripts/npm/updateChangeLog.js
+++ b/src/scripts/npm/updateChangeLog.js
@@ -1,3 +1,5 @@
+"use strict";
+
 // TODO: test git push
 // TODO: early exit based on last changelog version
 // TODO: 'Authorization': 'token xxxx', for testing
diff --git a/src/scripts/npm/updateNpmVersion.js b/src/scripts/npm/updateNpmVersion.js
index bc4a9f6c..451cda49 100644
--- a/src/scripts/npm/updateNpmVersion.js
+++ b/src/scripts/npm/updateNpmVersion.js
@@ -1,3 +1,5 @@
+"use strict";
+
 (function() {
   // properties