diff --git a/src/interfaces.ts b/src/interfaces.ts
index 2c06932..b7186e6 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -14,7 +14,7 @@ export interface IBaseColorSet  {
 }
 
 export interface IColorSet {
-  type: 'light' | 'dark';
+  type?: 'light' | 'dark';
   base: IBaseColorSet;
   syntax?: {
     boolean?: string;
diff --git a/src/vscodeThemeGenerator.ts b/src/vscodeThemeGenerator.ts
index 9633806..557f097 100644
--- a/src/vscodeThemeGenerator.ts
+++ b/src/vscodeThemeGenerator.ts
@@ -12,6 +12,7 @@ export interface IVscodeJsonTheme {
 export class VscodeThemeGenerator implements IThemeGenerator {
   public generateTheme(name: string, colorSet: IColorSet): string {
     // Fill in missing subsets to prevent NPEs
+    if (!colorSet.type) colorSet.type = 'dark';
     if (!colorSet.syntax) colorSet.syntax = {};
     if (!colorSet.terminal) colorSet.terminal = {};
     if (!colorSet.ui) colorSet.ui = {};