Fix schema objects with default + nullable

package.json

@@ -17,7 +17,7 @@
   "devDependencies": {
     "@biomejs/biome": "^1.7.3",
     "@changesets/changelog-github": "^0.5.0",
-    "@changesets/cli": "^2.27.1",
+    "@changesets/cli": "^2.27.2",
     "del-cli": "^5.1.0",
     "prettier": "^3.2.5",
     "typescript": "^5.4.5"

packages/openapi-typescript/examples/digital-ocean-api.ts

@@ -9894,7 +9894,7 @@ export interface components {
              *       "web"
              *     ]
              */
-            tags: string[] | null;
+            tags: string[];
             /**
              * @description A string containing 'user data' which may be used to configure the Droplet on first boot, often a 'cloud-config' file or Bash script. It must be plain text and may not exceed 64 KiB in size.
              * @example #cloud-config

packages/openapi-typescript/examples/github-api-export-type-immutable.ts

@@ -29148,7 +29148,7 @@ export type components = {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT" | null;
+            readonly start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -30255,7 +30255,7 @@ export type components = {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT" | null;
+            readonly start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -101600,7 +101600,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 readonly task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                readonly environment?: string | null;
+                readonly environment?: string;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 readonly per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */

packages/openapi-typescript/examples/github-api-immutable.ts

@@ -29148,7 +29148,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT" | null;
+            readonly start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -30255,7 +30255,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT" | null;
+            readonly start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -101600,7 +101600,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 readonly task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                readonly environment?: string | null;
+                readonly environment?: string;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 readonly per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */

packages/openapi-typescript/examples/github-api-next.ts

@@ -101899,7 +101899,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string | null;
+                environment?: string;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */

packages/openapi-typescript/examples/github-api.ts

@@ -29148,7 +29148,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT" | null;
+            start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -30255,7 +30255,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT" | null;
+            start_side: "LEFT" | "RIGHT";
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -101600,7 +101600,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string | null;
+                environment?: string;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */

packages/openapi-typescript/src/transform/schema-object.ts

@@ -116,7 +116,10 @@ export function transformSchemaObjectWithComposition(
       return ts.factory.createTypeReferenceNode(enumType.name);
     }
     const enumType = schemaObject.enum.map(tsLiteral);
-    if ((Array.isArray(schemaObject.type) && schemaObject.type.includes("null")) || schemaObject.nullable) {
+    if (
+      ((Array.isArray(schemaObject.type) && schemaObject.type.includes("null")) || schemaObject.nullable) &&
+      !schemaObject.default
+    ) {
       enumType.push(NULL);
     }
 
@@ -242,7 +245,7 @@ export function transformSchemaObjectWithComposition(
   // if final type could be generated, return intersection of all members
   if (finalType) {
     // deprecated nullable
-    if (schemaObject.nullable) {
+    if (schemaObject.nullable && !schemaObject.default) {
       return tsNullable([finalType]);
     }
     return finalType;
@@ -364,7 +367,7 @@ function transformSchemaObjectCore(schemaObject: SchemaObject, options: Transfor
     // polymorphic, or 3.1 nullable
     if (Array.isArray(schemaObject.type) && !Array.isArray(schemaObject)) {
       // skip any primitive types that appear in oneOf as well
-      let uniqueTypes: ts.TypeNode[] = [];
+      const uniqueTypes: ts.TypeNode[] = [];
       if (Array.isArray(schemaObject.oneOf)) {
         for (const t of schemaObject.type) {
           if (
@@ -383,11 +386,15 @@ function transformSchemaObjectCore(schemaObject: SchemaObject, options: Transfor
           );
         }
       } else {
-        uniqueTypes = schemaObject.type.map((t) =>
-          t === "null" || t === null
-            ? NULL
-            : transformSchemaObject({ ...schemaObject, type: t } as SchemaObject, options),
-        );
+        for (const t of schemaObject.type) {
+          if (t === "null" || t === null) {
+            if (!schemaObject.default) {
+              uniqueTypes.push(NULL);
+            }
+          } else {
+            uniqueTypes.push(transformSchemaObject({ ...schemaObject, type: t } as SchemaObject, options));
+          }
+        }
       }
       return tsUnion(uniqueTypes);
     }

packages/openapi-typescript/test/transform/schema-object/string.test.ts

@@ -91,6 +91,27 @@ describe("transformSchemaObject > string", () => {
         want: '"A" | "B" | "C" | null',
       },
     ],
+    [
+      "default + nullable",
+      {
+        given: { type: ["string", "null"], default: "en" },
+        want: "string",
+      },
+    ],
+    [
+      "default + nullable + enum",
+      {
+        given: { type: ["string", "null"], enum: ["en", "es", "fr", "de"], default: "en" },
+        want: '"en" | "es" | "fr" | "de"',
+      },
+    ],
+    [
+      "default + nullable (deprecated syntax)",
+      {
+        given: { type: "string", default: "en", nullable: true },
+        want: "string",
+      },
+    ],
   ];
 
   for (const [testName, { given, want, options = DEFAULT_OPTIONS, ci }] of tests) {