diff --git a/frontend-js/src/main/js/InvalidArgumentError.js b/frontend-js/src/main/js/InvalidArgumentError.js
index 3833bbf547eca95a26c8a28ad6301fc60c207a72..1c4f45fc9850a6421392236a5fa7e28483fffae2 100644
--- a/frontend-js/src/main/js/InvalidArgumentError.js
+++ b/frontend-js/src/main/js/InvalidArgumentError.js
@@ -10,4 +10,6 @@ function InvalidArgumentError(message) {
   this.stack = (new Error()).stack;
 }
 
+InvalidArgumentError.prototype = new Error
+
 module.exports = InvalidArgumentError;
diff --git a/frontend-js/src/main/js/InvalidCredentialsError.js b/frontend-js/src/main/js/InvalidCredentialsError.js
index 424ad4785c59b7a2ae85e47e2d42f1171b863c01..f0de8ad8313582137435553e901efc3c60ebf3db 100644
--- a/frontend-js/src/main/js/InvalidCredentialsError.js
+++ b/frontend-js/src/main/js/InvalidCredentialsError.js
@@ -10,4 +10,6 @@ function InvalidCredentialsError(message) {
   this.stack = (new Error()).stack;
 }
 
+InvalidCredentialsError.prototype = new Error
+
 module.exports = InvalidCredentialsError;
diff --git a/frontend-js/src/main/js/NetworkError.js b/frontend-js/src/main/js/NetworkError.js
index e1f3637707ef2e589fd8fd7c66ce4be762a088c5..c5210ccebf006811c74dd01fd2963108bfd1341a 100644
--- a/frontend-js/src/main/js/NetworkError.js
+++ b/frontend-js/src/main/js/NetworkError.js
@@ -16,4 +16,6 @@ function NetworkError(message, connectionParams) {
   this.content = connectionParams.content;
 }
 
+NetworkError.prototype = new Error
+
 module.exports = NetworkError;