refactor: use optional chaining in template params validation (#1299)

Co-authored-by: Lukasz Gornicki <[email protected]>

apps/generator/lib/generator.js

@@ -134,7 +134,7 @@ class Generator {
       Object.defineProperty(this.templateParams, key, {
         enumerable: true,
         get() {
-          if (!self.templateConfig.parameters || !self.templateConfig.parameters[key]) {
+          if (!self.templateConfig.parameters?.[key]) {
             throw new Error(`Template parameter "${key}" has not been defined in the package.json file under generator property. Please make sure it's listed there before you use it in your template.`);
           }
           return templateParams[key];