feat: add validationMetadataArrayToSchemas and targetConstructorToSchema functions (#62)

* feat: add validationMetadataArrayToSchemas and targetConstructorToSchema functions

* Update src/index.ts

Co-authored-by: Aleksi Pekkala <aleksipekkala@gmail.com>

* Update src/index.ts

Co-authored-by: Aleksi Pekkala <aleksipekkala@gmail.com>

Author: NexZhu

__tests__/index.test.ts

@@ -15,7 +15,7 @@ import {
   ValidateNested,
 } from 'class-validator'
 import { ValidationMetadata } from 'class-validator/types/metadata/ValidationMetadata'
-import { validationMetadatasToSchemas } from '../src'
+import { targetConstructorToSchema, validationMetadatasToSchemas } from '../src'
 
 class User {
   @IsString() id: string
@@ -159,6 +159,70 @@ describe('classValidatorConverter', () => {
     })
   })
 
+  it('combines converted class-validator metadata for one object into JSON Schemas', () => {
+    const postSchema = targetConstructorToSchema(Post)
+
+    expect(postSchema).toEqual({
+      properties: {
+        published: {
+          type: 'boolean',
+        },
+        title: {
+          maxLength: 100,
+          minLength: 2,
+          type: 'string',
+        },
+        user: {
+          $ref: '#/definitions/User',
+        },
+      },
+      type: 'object',
+    })
+
+    const userSchema = targetConstructorToSchema(User)
+
+    expect(userSchema).toEqual({
+      properties: {
+        empty: {
+          anyOf: [
+            { type: 'string', enum: [''] },
+            {
+              not: {
+                anyOf: [
+                  { type: 'string' },
+                  { type: 'number' },
+                  { type: 'boolean' },
+                  { type: 'integer' },
+                  { type: 'array' },
+                  { type: 'object' },
+                ],
+              },
+              nullable: true,
+            },
+          ],
+        },
+        firstName: { minLength: 5, type: 'string' },
+        id: { type: 'string' },
+        object: { type: 'object' },
+        nonEmptyObject: { type: 'object', minProperties: 1 },
+        any: {},
+        tags: {
+          items: {
+            maxLength: 20,
+            not: {
+              anyOf: [{ enum: ['admin'], type: 'string' }],
+            },
+            type: 'string',
+          },
+          maxItems: 5,
+          type: 'array',
+        },
+      },
+      required: ['id', 'firstName', 'object', 'any'],
+      type: 'object',
+    })
+  })
+
   it('should use custom schema name field', () => {
     const schemas = validationMetadatasToSchemas({
       schemaNameField: 'schemaName',

src/index.ts

@@ -15,7 +15,9 @@ export { JSONSchema } from './decorators'
 /**
  * Convert class-validator metadata into JSON Schema definitions.
  */
-export function validationMetadatasToSchemas(userOptions?: Partial<IOptions>) {
+export function validationMetadatasToSchemas(
+  userOptions?: Partial<IOptions>
+): Record<string, SchemaObject> {
   const options: IOptions = {
     ...defaultOptions,
     ...userOptions,
@@ -25,6 +27,21 @@ export function validationMetadatasToSchemas(userOptions?: Partial<IOptions>) {
     options.classValidatorMetadataStorage
   )
 
+  return validationMetadataArrayToSchemas(metadatas, userOptions)
+}
+
+/**
+ * Convert an array of class-validator metadata into JSON Schema definitions.
+ */
+export function validationMetadataArrayToSchemas(
+  metadatas: ValidationMetadata[],
+  userOptions?: Partial<IOptions>
+): Record<string, SchemaObject> {
+  const options: IOptions = {
+    ...defaultOptions,
+    ...userOptions,
+  }
+
   const schemas: { [key: string]: SchemaObject } = {}
   Object.entries(
     _groupBy(
@@ -74,13 +91,45 @@ export function validationMetadatasToSchemas(userOptions?: Partial<IOptions>) {
   return schemas
 }
 
+/**
+ * Generate JSON Schema definitions from the target object constructor.
+ */
+export function targetConstructorToSchema(
+  targetConstructor: Function,
+  userOptions?: Partial<IOptions>
+): SchemaObject {
+  const options: IOptions = {
+    ...defaultOptions,
+    ...userOptions,
+  }
+
+  const storage = options.classValidatorMetadataStorage
+  let metadatas = storage.getTargetValidationMetadatas(
+    targetConstructor,
+    '',
+    true,
+    false
+  )
+  metadatas = populateMetadatasWithConstraints(storage, metadatas)
+
+  const schemas = validationMetadataArrayToSchemas(metadatas, userOptions)
+  return Object.values(schemas).length ? Object.values(schemas)[0] : {}
+}
+
 /**
  * Return `storage.validationMetadatas` populated with `constraintMetadatas`.
  */
 function getMetadatasFromStorage(
   storage: cv.MetadataStorage
 ): ValidationMetadata[] {
   const metadatas: ValidationMetadata[] = (storage as any).validationMetadatas
+  return populateMetadatasWithConstraints(storage, metadatas)
+}
+
+function populateMetadatasWithConstraints(
+  storage: cv.MetadataStorage,
+  metadatas: ValidationMetadata[]
+): ValidationMetadata[] {
   const constraints: ConstraintMetadata[] = (storage as any).constraintMetadatas
 
   return metadatas.map((meta) => {