diff --git a/src/helpers/packageJson.js b/src/helpers/packageJson.js
index aa20aba0d32da2c562badbbc2c9ed89b535d83e0..60d95ac2ebb58d33ca317822d6c7cd3f98d84107 100644
--- a/src/helpers/packageJson.js
+++ b/src/helpers/packageJson.js
@@ -41,5 +41,5 @@ function matchAt(content, index, match) {
 
 // Replace oldString with newString at location index of content
 function replaceAt(content, index, oldString, newString) {
-  return content.substr(0, index) + newString + content.substr(index, oldString.length);
+  return content.substr(0, index) + newString + content.substr(index + oldString.length);
 }