Fixed null based kotlin union type into optionals

Author: serkangunes

rollup.config.mjs

@@ -34,6 +34,7 @@ const handlebarsPlugin = () => ({
                     notEquals: true,
                     containsSpaces: true,
                     union: true,
+                    kotlinUnion: true,
                     intersection: true,
                     enumerator: true,
                     escapeComment: true,

src/templates/partials/typeKotlin.hbs

@@ -9,9 +9,9 @@
 {{else equals export 'dictionary'}}
 {{>typeKotlinDictionary}}
 {{else equals export 'one-of'}}
-typeUnion {{>typeUnion}}
+typeUnionOneOf {{>typeKotlinUnion}}
 {{else equals export 'any-of'}}
-typeUnion {{>typeUnion}}
+{{>typeKotlinUnion}}
 {{else equals export 'all-of'}}
 typeIntersection {{>typeIntersection}}
 {{else}}

src/templates/partials/typeKotlinUnion.hbs

@@ -0,0 +1 @@
+{{~#kotlinUnion properties parent}}{{this}}{{~/kotlinUnion}}{{>isNullable}}

src/utils/registerHandlebarHelpers.spec.ts

@@ -16,6 +16,7 @@ describe('registerHandlebarHelpers', () => {
         expect(helpers).toContain('notEquals');
         expect(helpers).toContain('containsSpaces');
         expect(helpers).toContain('union');
+        expect(helpers).toContain('kotlinUnion');
         expect(helpers).toContain('intersection');
         expect(helpers).toContain('enumerator');
         expect(helpers).toContain('escapeComment');

src/utils/registerHandlebarHelpers.ts

@@ -55,6 +55,25 @@ export const registerHandlebarHelpers = (root: {
         }
     );
 
+    Handlebars.registerHelper(
+        'kotlinUnion',
+        function (this: any, properties: Model[], parent: string | undefined, options: Handlebars.HelperOptions) {
+            const type = Handlebars.partials['typeKotlin'];
+            const types = properties.map(property => type({ ...root, ...property, parent }));
+            const uniqueTypes = types.filter(unique);
+            let uniqueTypesString = uniqueTypes.join(' | ');
+            if (uniqueTypes.includes('null') && uniqueTypes.length === 2) {
+                uniqueTypesString = `${uniqueTypes.filter(type => type !== 'null')[0]}?`;
+            } else {
+                uniqueTypesString = uniqueTypes.join(' | ');
+                if (uniqueTypes.length > 1) {
+                    uniqueTypesString = `(${uniqueTypesString})`;
+                }
+            }
+            return options.fn(uniqueTypesString);
+        }
+    );
+
     Handlebars.registerHelper(
         'intersection',
         function (this: any, properties: Model[], parent: string | undefined, options: Handlebars.HelperOptions) {

src/utils/registerHandlebarTemplates.ts

@@ -93,6 +93,7 @@ import partialTypeKotlinEnum from '../templates/partials/typeKotlinEnum.hbs';
 import partialTypeKotlinReference from '../templates/partials/typeKotlinReference.hbs';
 import partialTypeReference from '../templates/partials/typeReference.hbs';
 import partialTypeUnion from '../templates/partials/typeUnion.hbs';
+import partialTypeKotlinUnion from '../templates/partials/typeKotlinUnion.hbs';
 import { registerHandlebarHelpers } from './registerHandlebarHelpers';
 
 export interface Templates {
@@ -183,6 +184,7 @@ export const registerHandlebarTemplates = (root: {
     Handlebars.registerPartial('typeReference', Handlebars.template(partialTypeReference));
     Handlebars.registerPartial('typeKotlinReference', Handlebars.template(partialTypeKotlinReference));
     Handlebars.registerPartial('typeUnion', Handlebars.template(partialTypeUnion));
+    Handlebars.registerPartial('typeKotlinUnion', Handlebars.template(partialTypeKotlinUnion));
     Handlebars.registerPartial('typeIntersection', Handlebars.template(partialTypeIntersection));
     Handlebars.registerPartial('base', Handlebars.template(partialBase));
     Handlebars.registerPartial('baseKotlin', Handlebars.template(partialBaseKotlin));