Merge pull request #111 from alesandroLang/extends

added support for the "extends" keyword

README.md

@@ -134,7 +134,7 @@ json2ts -i foo.json -o foo.d.ts
 - [x] `anyOf` ("union")
 - [x] `oneOf` (treated like `anyOf`)
 - [x] `additionalProperties` of type
-- [ ] [`extends`](https://github.com/json-schema/json-schema/wiki/Extends)
+- [x] [`extends`](https://github.com/json-schema/json-schema/wiki/Extends)
 - [x] `required` properties on objects ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L130))
 - [ ] `validateRequired` ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L124))
 - [x] literal objects in enum ([eg](https://github.com/tdegrunt/jsonschema/blob/67c0e27ce9542efde0bf43dc1b2a95dd87df43c3/examples/all.js#L236))

src/generator.ts

@@ -37,7 +37,7 @@ function declareEnums(
       type = generateStandaloneEnum(ast, options) + '\n'
       break
     case 'INTERFACE':
-      type = ast.params.reduce((prev, { ast }) =>
+      type = getSuperTypesAndParams(ast).reduce((prev, ast) =>
         prev + declareEnums(ast, options, processed),
         '')
       break
@@ -69,7 +69,7 @@ function declareNamedInterfaces(
     case 'INTERFACE':
       type = [
         hasStandaloneName(ast) && (ast.standaloneName === rootASTName || options.declareExternallyReferenced) && generateStandaloneInterface(ast, options),
-        ast.params.map(({ ast }) =>
+        getSuperTypesAndParams(ast).map(ast =>
           declareNamedInterfaces(ast, options, rootASTName, processed)
         ).filter(Boolean).join('\n')
       ].filter(Boolean).join('\n')
@@ -109,7 +109,7 @@ function declareNamedTypes(
       type = ''
       break
     case 'INTERFACE':
-      type = ast.params.map(({ ast }) => declareNamedTypes(ast, options, processed)).filter(Boolean).join('\n')
+      type = getSuperTypesAndParams(ast).map(ast => declareNamedTypes(ast, options, processed)).filter(Boolean).join('\n')
       break
     case 'INTERSECTION':
     case 'UNION':
@@ -216,6 +216,7 @@ function generateStandaloneEnum(ast: TEnum, options: Options): string {
 function generateStandaloneInterface(ast: TNamedInterface, options: Options): string {
   return (hasComment(ast) ? generateComment(ast.comment, options, 0) + '\n' : '')
     + `export interface ${toSafeString(ast.standaloneName)} `
+    + (ast.superTypes.length > 0 ? `extends ${ast.superTypes.map(superType => toSafeString(superType.standaloneName)).join(', ')} ` : '')
     + generateInterface(ast, options, 0)
     + (options.enableTrailingSemicolonForInterfaces ? ';' : '')
 }
@@ -239,3 +240,9 @@ function escapeKeyName(keyName: string): string {
   }
   return JSON.stringify(keyName)
 }
+
+function getSuperTypesAndParams(ast: TInterface): AST[] {
+  return ast.params
+      .map(param => param.ast)
+      .concat(ast.superTypes)
+}

src/parser.ts

@@ -2,7 +2,7 @@ import { whiteBright } from 'cli-color'
 import { JSONSchema4Type, JSONSchema4TypeName } from 'json-schema'
 import { findKey, includes, isPlainObject, map } from 'lodash'
 import { typeOfSchema } from './typeOfSchema'
-import { AST, T_ANY, T_ANY_ADDITIONAL_PROPERTIES, TInterfaceParam } from './types/AST'
+import { AST, hasName, T_ANY, T_ANY_ADDITIONAL_PROPERTIES, TInterface, TInterfaceParam, TNamedInterface } from './types/AST'
 import { JSONSchema, JSONSchemaWithDefinitions, SchemaSchema } from './types/JSONSchema'
 import { error, log } from './utils'
 
@@ -102,13 +102,7 @@ function parseNonLiteral(
         type: 'ENUM'
       })
     case 'NAMED_SCHEMA':
-      return set({
-        comment: schema.description,
-        keyName,
-        params: parseSchema(schema as SchemaSchema, rootSchema, processed),
-        standaloneName: computeSchemaName(schema as SchemaSchema),
-        type: 'INTERFACE'
-      })
+      return set(newInterface(schema, rootSchema, processed, keyName))
     case 'NULL':
       return set({
         comment: schema.description,
@@ -182,14 +176,7 @@ function parseNonLiteral(
         type: 'UNION'
       })
     case 'UNNAMED_SCHEMA':
-      return set({
-        comment: schema.description,
-        keyName,
-        params: parseSchema(schema as SchemaSchema, rootSchema, processed),
-        standaloneName: computeSchemaName(schema as SchemaSchema)
-                     || keyNameFromDefinition,
-        type: 'INTERFACE'
-      })
+      return set(newInterface(schema, rootSchema, processed, keyName, keyNameFromDefinition))
     case 'UNTYPED_ARRAY':
       return set({
         comment: schema.description,
@@ -201,6 +188,39 @@ function parseNonLiteral(
   }
 }
 
+function newInterface(schema: JSONSchema, rootSchema: JSONSchema, processed: Map<JSONSchema | JSONSchema4Type, AST>, keyName?: string,
+                      keyNameFromDefinition?: string): TInterface {
+  return {
+    comment: schema.description,
+    keyName,
+    params: parseSchema(schema as SchemaSchema, rootSchema, processed),
+    standaloneName: computeSchemaName(schema as SchemaSchema) || keyNameFromDefinition,
+    superTypes: parseSuperTypes(schema as SchemaSchema, processed),
+    type: 'INTERFACE'
+  }
+}
+
+function parseSuperTypes(schema: SchemaSchema, processed: Map<JSONSchema | JSONSchema4Type, AST>): TNamedInterface[] {
+  // type assertion needed because of dereferencing step
+  const superTypes = schema.extends as SchemaSchema | SchemaSchema[] | undefined
+  if (typeof superTypes === 'undefined') {
+    return []
+  } else if (superTypes instanceof Array) {
+    return superTypes.map(superType => newNamedInterface(superType, superType, processed))
+  } else {
+    return [newNamedInterface(superTypes, superTypes, processed)]
+  }
+}
+
+function newNamedInterface(schema: JSONSchema, rootSchema: JSONSchema, processed: Map<JSONSchema | JSONSchema4Type, AST>): TNamedInterface {
+  const namedInterface = newInterface(schema, rootSchema, processed)
+  if (hasName(namedInterface)) {
+    return namedInterface
+  } else {
+    throw error('Supertype must have standalone name!', namedInterface)
+  }
+}
+
 /**
  * Compute a schema name using a series of fallbacks
  */

src/types/AST.ts

@@ -27,6 +27,10 @@ export function hasStandaloneName(ast: AST): ast is ASTWithStandaloneName {
   return 'standaloneName' in ast && ast.standaloneName != null && ast.standaloneName !== ''
 }
 
+export function hasName(ast: TInterface): ast is TNamedInterface {
+  return hasStandaloneName(ast)
+}
+
 ////////////////////////////////////////////     types
 
 export interface TAny extends AbstractAST {
@@ -56,12 +60,14 @@ export interface TEnumParam {
 export interface TInterface extends AbstractAST {
   type: 'INTERFACE'
   params: TInterfaceParam[]
+  superTypes: TNamedInterface[]
 }
 
 export interface TNamedInterface extends AbstractAST {
   standaloneName: string
   type: 'INTERFACE'
   params: TInterfaceParam[]
+  superTypes: TNamedInterface[]
 }
 
 export interface TInterfaceParam {

test/e2e/extends.1.ts

@@ -0,0 +1,51 @@
+export const input = {
+  "title": "Extends",
+  'type': "object",
+  "extends": {
+    "$ref": "test/resources/BaseType.1.json"
+  },
+  properties: {
+    "foo": {
+      "type": "string"
+    }
+  },
+  required: ["foo"],
+  additionalProperties: false
+}
+
+export const outputs = [
+  {
+    options: {
+      declareExternallyReferenced: true
+    },
+    output: `/**
+* This file was automatically generated by json-schema-to-typescript.
+* DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
+* and run json-schema-to-typescript to regenerate this file.
+*/
+
+export interface Extends extends Base1 {
+  foo: string;
+}
+export interface Base1 {
+  firstName: string;
+  lastName: string;
+}
+`
+  },
+  {
+    options: {
+      declareExternallyReferenced: false
+    },
+    output: `/**
+* This file was automatically generated by json-schema-to-typescript.
+* DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
+* and run json-schema-to-typescript to regenerate this file.
+*/
+
+export interface Extends extends Base1 {
+  foo: string;
+}
+`
+  }
+]

test/e2e/extends.2.ts

@@ -0,0 +1,59 @@
+export const input = {
+  "title": "Extends",
+  'type': "object",
+  "extends": [
+    {
+      "$ref": "test/resources/BaseType.1.json"
+    },
+    {
+      "$ref": "test/resources/BaseType.2.json"
+    }
+  ],
+  properties: {
+    "foo": {
+      "type": "string"
+    }
+  },
+  required: ["foo"],
+  additionalProperties: false
+}
+
+export const outputs = [
+  {
+    options: {
+      declareExternallyReferenced: true
+    },
+    output: `/**
+* This file was automatically generated by json-schema-to-typescript.
+* DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
+* and run json-schema-to-typescript to regenerate this file.
+*/
+
+export interface Extends extends Base1, Base2 {
+  foo: string;
+}
+export interface Base1 {
+  firstName: string;
+  lastName: string;
+}
+export interface Base2 {
+  age: number;
+}
+`
+  },
+  {
+    options: {
+      declareExternallyReferenced: false
+    },
+    output: `/**
+* This file was automatically generated by json-schema-to-typescript.
+* DO NOT MODIFY IT BY HAND. Instead, modify the source JSONSchema file,
+* and run json-schema-to-typescript to regenerate this file.
+*/
+
+export interface Extends extends Base1, Base2 {
+  foo: string;
+}
+`
+  }
+]

test/resources/BaseType.1.json

@@ -0,0 +1,15 @@
+{
+  "id": "http://dummy.com/api/base1",
+  "title": "Base1",
+  "type": "object",
+  "properties": {
+    "firstName": {
+      "type": "string"
+    },
+    "lastName": {
+      "type": "string"
+    }
+  },
+  "required": ["firstName", "lastName"],
+  "additionalProperties": false
+}

test/resources/BaseType.2.json

@@ -0,0 +1,12 @@
+{
+  "id": "http://dummy.com/api/base2",
+  "title": "Base2",
+  "type": "object",
+  "properties": {
+    "age": {
+      "type": "integer"
+    }
+  },
+  "required": ["age"],
+  "additionalProperties": false
+}