diff --git a/src/node-obfuscators/MemberExpressionObfuscator.ts b/src/node-obfuscators/MemberExpressionObfuscator.ts
index 3507c121..ea4a25c7 100644
--- a/src/node-obfuscators/MemberExpressionObfuscator.ts
+++ b/src/node-obfuscators/MemberExpressionObfuscator.ts
@@ -77,7 +77,7 @@ export class MemberExpressionObfuscator extends NodeObfuscator {
     private obfuscateLiteralProperty (node: ILiteralNode): void {
         if (typeof node.value === 'string' && !node['x-verbatim-property']) {
             node['x-verbatim-property'] = {
-                content : this.replaceLiteralValueWithUnicodeValue(node.value),
+                content : this.replaceLiteralValueWithUnicodeValue(<string>node.value),
                 precedence: escodegen.Precedence.Primary
             };
         }
diff --git a/src/node-obfuscators/ObjectExpressionObfuscator.ts b/src/node-obfuscators/ObjectExpressionObfuscator.ts
index 895f241e..220c2a89 100644
--- a/src/node-obfuscators/ObjectExpressionObfuscator.ts
+++ b/src/node-obfuscators/ObjectExpressionObfuscator.ts
@@ -52,7 +52,7 @@ export class ObjectExpressionObfuscator extends NodeObfuscator {
     private obfuscateLiteralPropertyKey (node: ILiteralNode): void {
         if (typeof node.value === 'string' && !node['x-verbatim-property']) {
             node['x-verbatim-property'] = {
-                content : Utils.stringToUnicode(node.value),
+                content : Utils.stringToUnicode(<string>node.value),
                 precedence: escodegen.Precedence.Primary
             };
         }