Fix wrong generated type when processing enums containing "null" (#492)

* add failing test

* fix generated type when processing enums containing "null"

Fix issue #482

* remove useless code

* avoid double null when enum contains null and is nullable

Co-authored-by: Federico Bevione <[email protected]>

Author: FedeBev

src/transform/schema.ts

@@ -67,9 +67,13 @@ export function transformSchemaObj(node: any): string {
       break;
     }
     case "enum": {
-      output += tsUnionOf(
-        (node.enum as string[]).map((item) => (typeof item === "string" ? `'${item.replace(/'/g, "\\'")}'` : item))
-      );
+      const items: Array<string | number | boolean> = [];
+      (node.enum as unknown[]).forEach((item) => {
+        if (typeof item === "string") items.push(`'${item.replace(/'/g, "\\'")}'`);
+        else if (typeof item === "number" || typeof item === "boolean") items.push(item);
+        else if (item === null && !node.nullable) items.push("null");
+      });
+      output += tsUnionOf(items);
       break;
     }
     case "object": {

src/utils.ts

@@ -125,8 +125,8 @@ export function tsPartial(type: string): string {
 }
 
 /** Convert [X, Y, Z] into X | Y | Z */
-export function tsUnionOf(types: string[]): string {
-  if (types.length === 1) return types[0]; // don’t add parentheses around one thing
+export function tsUnionOf(types: Array<string | number | boolean>): string {
+  if (types.length === 1) return `${types[0]}`; // don’t add parentheses around one thing
   return `(${types.join(") | (")})`;
 }
 

tests/schema.test.ts

@@ -103,6 +103,46 @@ describe("SchemaObject", () => {
       ).toBe(`{
 "string"?: ('Totoro') | ('Sats\\'uki') | ('Mei');
 
+}`);
+
+      expect(
+        transform({
+          properties: { string: { type: "string", enum: ["Totoro", "Sats'uki", "Mei", null] } }, // note: also tests quotes in enum
+          type: "object",
+        })
+      ).toBe(`{
+"string"?: ('Totoro') | ('Sats\\'uki') | ('Mei') | (null);
+
+}`);
+
+      expect(
+        transform({
+          properties: { string: { type: "string", enum: ["Totoro", 2, false, null] } }, // note: also tests quotes in enum
+          type: "object",
+        })
+      ).toBe(`{
+"string"?: ('Totoro') | (2) | (false) | (null);
+
+}`);
+
+      expect(
+        transform({
+          properties: { string: { type: "string", enum: ["Totoro", 2, false, null], nullable: true } }, // note: also tests quotes in enum
+          type: "object",
+        })
+      ).toBe(`{
+"string"?: (('Totoro') | (2) | (false)) | null;
+
+}`);
+
+      expect(
+        transform({
+          properties: { string: { type: "string", enum: ["Totoro", 2, false], nullable: true } }, // note: also tests quotes in enum
+          type: "object",
+        })
+      ).toBe(`{
+"string"?: (('Totoro') | (2) | (false)) | null;
+
 }`);
     });
 

tests/v2/expected/null-in-enum.ts

@@ -0,0 +1,38 @@
+/**
+ * This file was auto-generated by openapi-typescript.
+ * Do not make direct changes to the file.
+ */
+
+export interface paths {
+  "/test": {
+    post: operations["addTest"];
+  };
+}
+
+export interface definitions {
+  /** Enum with null and nullable */
+  MyType: {
+    myField?: ("foo" | "bar") | null;
+  };
+  /** Enum with null */
+  MyTypeNotNullable: {
+    myField?: "foo" | "bar" | null;
+  };
+  /** Enum with null */
+  MyTypeNotNullableNotNull: {
+    myField?: "foo" | "bar";
+  };
+  /** Enum with null */
+  MyTypeMixed: {
+    myField?: "foo" | 2 | false | null;
+  };
+}
+
+export interface operations {
+  addTest: {
+    responses: {
+      /** OK */
+      200: unknown;
+    };
+  };
+}

tests/v2/specs/null-in-enum.yaml

@@ -0,0 +1,48 @@
+swagger: 2.0
+paths:
+  /test:
+    post:
+      tags:
+        - "test"
+      summary: "Just a test path"
+      description: ""
+      operationId: "addTest"
+      consumes:
+        - "application/json"
+        - "application/xml"
+      produces:
+        - "application/xml"
+        - "application/json"
+      responses:
+        200:
+          description: "OK"
+definitions:
+  MyType:
+    description: Enum with null and nullable
+    type: object
+    properties:
+      myField:
+        type: string
+        enum: ["foo", "bar", null]
+        nullable: true
+  MyTypeNotNullable:
+    description: Enum with null
+    type: object
+    properties:
+      myField:
+        type: string
+        enum: ["foo", "bar", null]
+  MyTypeNotNullableNotNull:
+    description: Enum with null
+    type: object
+    properties:
+      myField:
+        type: string
+        enum: ["foo", "bar"]
+  MyTypeMixed:
+    description: Enum with null
+    type: object
+    properties:
+      myField:
+        type: string
+        enum: ["foo", 2, false, null]

tests/v3/expected/null-in-enum.ts

@@ -0,0 +1,38 @@
+/**
+ * This file was auto-generated by openapi-typescript.
+ * Do not make direct changes to the file.
+ */
+
+export interface paths {
+  "/test": {
+    get: {
+      responses: {
+        /** A list of types. */
+        200: unknown;
+      };
+    };
+  };
+}
+
+export interface components {
+  schemas: {
+    /** Enum with null and nullable */
+    MyType: {
+      myField?: ("foo" | "bar") | null;
+    };
+    /** Enum with null */
+    MyTypeNotNullable: {
+      myField?: "foo" | "bar" | null;
+    };
+    /** Enum with null */
+    MyTypeNotNullableNotNull: {
+      myField?: "foo" | "bar";
+    };
+    /** Enum with null */
+    MyTypeMixed: {
+      myField?: "foo" | 2 | false | null;
+    };
+  };
+}
+
+export interface operations {}

tests/v3/specs/null-in-enum.yaml

@@ -0,0 +1,41 @@
+openapi: 3.0
+paths:
+  /test:
+    get:
+      tags:
+        - test
+      summary: "Just a test path"
+      responses:
+        200:
+          description: A list of types.
+components:
+  schemas:
+    MyType:
+      description: Enum with null and nullable
+      type: object
+      properties:
+        myField:
+          type: string
+          enum: ["foo", "bar", null]
+          nullable: true
+    MyTypeNotNullable:
+      description: Enum with null
+      type: object
+      properties:
+        myField:
+          type: string
+          enum: ["foo", "bar", null]
+    MyTypeNotNullableNotNull:
+      description: Enum with null
+      type: object
+      properties:
+        myField:
+          type: string
+          enum: ["foo", "bar"]
+    MyTypeMixed:
+      description: Enum with null
+      type: object
+      properties:
+        myField:
+          type: string
+          enum: ["foo", 2, false, null]