fix: top-level discriminator using enum (#494)

* fix: #482 discriminator with enums

* fix: discriminator with enums #482

* fix: node 10

src/middlewares/parsers/request.schema.preprocessor.ts

@@ -7,6 +7,13 @@ type SchemaObject = OpenAPIV3.SchemaObject;
 type ReferenceObject = OpenAPIV3.ReferenceObject;
 type Schema = ReferenceObject | SchemaObject;
 
+if (!Array.prototype['flatMap']) {
+  // polyfill flatMap
+  // TODO remove me when dropping node 10 support
+  Array.prototype['flatMap'] = function (lambda) {
+    return Array.prototype.concat.apply([], this.map(lambda));
+  };
+}
 const httpMethods = new Set([
   'get',
   'put',
@@ -122,14 +129,15 @@ export class RequestSchemaPreprocessor {
 
     const xOf = schemaObj.oneOf ? 'oneOf' : 'anyOf';
     if (schemaObj?.discriminator?.propertyName && !o.discriminator) {
-      // TODO discriminator can be used for anyOf too!
-      const options = schemaObj[xOf].map((refObject) => {
-        const option = this.findKey(
+      const options = schemaObj[xOf].flatMap((refObject) => {
+        const keys = this.findKeys(
           schemaObj.discriminator.mapping,
           (value) => value === refObject['$ref'],
         );
         const ref = this.getKeyFromRef(refObject['$ref']);
-        return { option: option || ref, ref };
+        return keys.length > 0
+          ? keys.map((option) => ({ option, ref }))
+          : [{ option: ref, ref }];
       });
       o.options = options;
       o.discriminator = schemaObj.discriminator?.propertyName;
@@ -145,13 +153,16 @@ export class RequestSchemaPreprocessor {
       );
     } else if (schemaObj) {
       const ancestor: any = parent;
-      const option =
-        this.findKey(
-          ancestor.discriminator?.mapping,
-          (value) => value === schema['$ref'],
-        ) || this.getKeyFromRef(schema['$ref']);
+      const options = this.findKeys(
+        ancestor.discriminator?.mapping,
+        (value) => value === schema['$ref'],
+      );
+      const ref = this.getKeyFromRef(schema['$ref']);
+      if (options.length === 0 && ref) {
+        options.push(ref);
+      }
 
-      if (option) {
+      if (options.length > 0) {
         const newSchema = JSON.parse(JSON.stringify(schemaObj));
         newSchema.properties = {
           ...(o.properties ?? {}),
@@ -166,9 +177,12 @@ export class RequestSchemaPreprocessor {
           options: o.options,
           property: o.discriminator,
         };
-        ancestor._discriminator.validators[option] = this.ajv.compile(
-          newSchema,
-        );
+
+        for (const option of options) {
+          ancestor._discriminator.validators[option] = this.ajv.compile(
+            newSchema,
+          );
+        }
       }
       //reset data
       o.properties = {};
@@ -194,17 +208,20 @@ export class RequestSchemaPreprocessor {
     }
   }
 
-  private findKey(object, searchFunc) {
+  private findKeys(object, searchFunc): string[] {
+    const matches = [];
     if (!object) {
-      return;
+      return matches;
     }
     const keys = Object.keys(object);
     for (let i = 0; i < keys.length; i++) {
       if (searchFunc(object[keys[i]])) {
-        return keys[i];
+        matches.push(keys[i]);
       }
     }
+    return matches;
   }
+
   getKeyFromRef(ref) {
     return ref.split('/components/schemas/')[1];
   }

test/one.of.2.spec.ts

@@ -2,9 +2,8 @@ import * as path from 'path';
 import { expect } from 'chai';
 import * as request from 'supertest';
 import { createApp } from './common/app';
-import * as packageJson from '../package.json';
 
-describe('one.of.2.spec', () => {
+describe('oneOf with discriminator', () => {
   let app = null;
 
   before(async () => {
@@ -94,7 +93,7 @@ describe('one.of.2.spec', () => {
         .expect(400)
         .then((r) => {
           const e = r.body;
-          expect(e.message).to.include('one of the allowed values: cat, dog');
+          expect(e.message).to.include('one of the allowed values: cat, kitty, dog, puppy');
         }));
 
     it('should return 200 for dog', async () =>
@@ -108,14 +107,36 @@ describe('one.of.2.spec', () => {
         })
         .expect(200));
 
+    it('should return 200 for puppy', async () =>
+      request(app)
+        .post(`${app.basePath}/pets`)
+        .set('content-type', 'application/json')
+        .send({
+          pet_type: 'puppy',
+          bark: true,
+          breed: 'Dingo',
+        })
+        .expect(200));
+
     it('should return 200 for cat', async () =>
       request(app)
         .post(`${app.basePath}/pets`)
         .set('content-type', 'application/json')
         .send({
           pet_type: 'cat',
           hunts: true,
-          age: 3,
+          age: 1,
+        })
+        .expect(200));
+
+    it('should return 200 for kitty', async () =>
+      request(app)
+        .post(`${app.basePath}/pets`)
+        .set('content-type', 'application/json')
+        .send({
+          pet_type: 'kitty',
+          hunts: true,
+          age: 1,
         })
         .expect(200));
   });
@@ -160,4 +181,4 @@ describe('one.of.2.spec', () => {
         })
         .expect(200));
   });
-});
+});

test/resources/one.of.2.yaml

@@ -1,7 +1,7 @@
 openapi: '3.0.3'
 info:
   version: 1.0.0
-  title: Swagger 
+  title: Swagger
 servers:
   - url: /v1
 paths:
@@ -38,11 +38,13 @@ paths:
                 propertyName: pet_type
                 mapping:
                   cat: '#/components/schemas/CatObject'
+                  kitty: '#/components/schemas/CatObject'
                   dog: '#/components/schemas/DogObject'
+                  puppy: '#/components/schemas/DogObject'
       responses:
         '200':
           description: Updated
-          
+
   /pets_all:
     post:
       description: Creates a new pet in the store.
@@ -80,6 +82,10 @@ components:
           enum: [Dingo, Husky, Retriever, Shepherd]
         pet_type:
           type: string
+          # since we use an enum here
+          # add DogObject as an option
+          # so that the non-mapping / implied mapping tests can pass
+          enum: [dog, puppy, DogObject]
 
     CatObject:
       type: object
@@ -94,7 +100,11 @@ components:
           type: integer
         pet_type:
           type: string
-
+          # since we use an enum here
+          # add CatObject as an option
+          # so that the non-mapping / implied mapping tests can pass
+          enum: [cat, kitty, CatObject]
+
     Pet:
       type: object
       required:
@@ -106,7 +116,7 @@ components:
         propertyName: pet_type
 
     Dog:     # "Dog" is a value for the pet_type property (the discriminator value)
-      allOf: # Combines the main `Pet` schema with `Dog`-specific properties 
+      allOf: # Combines the main `Pet` schema with `Dog`-specific properties
         - $ref: '#/components/schemas/Pet'
         - type: object
           # all other properties specific to a `Dog`
@@ -117,7 +127,7 @@ components:
               type: string
               enum: [Dingo, Husky, Retriever, Shepherd]
     Cat:     # "Cat" is a value for the pet_type property (the discriminator value)
-      allOf: # Combines the main `Pet` schema with `Cat`-specific properties 
+      allOf: # Combines the main `Pet` schema with `Cat`-specific properties
         - $ref: '#/components/schemas/Pet'
         - type: object
           # all other properties specific to a `Cat`

tsconfig.json

@@ -1,8 +1,8 @@
 {
   "compilerOptions": {
     "declaration": true,
-    "target": "ES2017",
-    "lib": ["ES2017"],
+    "target": "es2017",
+    "lib": ["es2019", "es2019.array"],
     "module": "commonjs",
     "moduleResolution": "node",
     "outDir": "dist",