Fix additionalProperties handling (#7)

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>

Author: jviotti

src/generator/typescript.cc

@@ -91,11 +91,7 @@ auto TypeScript::operator()(const IRObject &entry) const -> void {
     return;
   }
 
-  if (has_additional) {
-    this->output << "export type " << type_name << " = {\n";
-  } else {
-    this->output << "export interface " << type_name << " {\n";
-  }
+  this->output << "export interface " << type_name << " {\n";
 
   // We always quote property names for safety. JSON Schema allows any string
   // as a property name, but unquoted TypeScript/ECMAScript property names
@@ -115,32 +111,24 @@ auto TypeScript::operator()(const IRObject &entry) const -> void {
   }
 
   if (has_additional) {
-    this->output << "} & {\n";
-
-    // While we could do this with the more idiomatic `Record<Exclude<string,
-    // X>, Y>`, we choose the more verbose manner in order to allow users to
-    // declare a type called `Record`
-    this->output << "  [K in string as K extends\n";
-
-    std::size_t index{0};
+    // TypeScript index signatures must be a supertype of all property value
+    // types. We use a union of all member types plus the additional properties
+    // type plus undefined (for optional properties).
+    this->output << "  [key: string]:\n";
     for (const auto &[member_name, member_value] : entry.members) {
-      const auto is_last{index == entry.members.size() - 1};
-      this->output << "    \"" << escape_string(member_name) << "\"";
-      if (!is_last) {
-        this->output << " |";
-      }
-      this->output << "\n";
-      ++index;
+      this->output << "    "
+                   << sourcemeta::core::mangle(member_value.pointer,
+                                               this->prefix)
+                   << " |\n";
     }
-
-    this->output << "  ? never : K]: "
+    this->output << "    "
                  << sourcemeta::core::mangle(entry.additional->pointer,
                                              this->prefix)
-                 << ";\n";
-    this->output << "};\n";
-  } else {
-    this->output << "}\n";
+                 << " |\n";
+    this->output << "    undefined;\n";
   }
+
+  this->output << "}\n";
 }
 
 auto TypeScript::operator()(const IRImpossible &entry) const -> void {

src/ir/include/sourcemeta/codegen/ir.h

@@ -64,7 +64,7 @@ struct IRObjectValue : IRType {
 struct IRObject : IRType {
   // To preserve the user's ordering
   std::vector<std::pair<sourcemeta::core::JSON::String, IRObjectValue>> members;
-  std::optional<IRObjectValue> additional;
+  std::optional<IRType> additional;
 };
 
 /// @ingroup ir

src/ir/ir_default_compiler.h

@@ -96,13 +96,16 @@ auto handle_object(const sourcemeta::core::JSON &schema,
     members.emplace_back(entry.first, std::move(member_value));
   }
 
-  std::optional<IRObjectValue> additional{std::nullopt};
+  std::optional<IRType> additional{std::nullopt};
   if (subschema.defines("additionalProperties")) {
-    auto additional_pointer{sourcemeta::core::to_pointer(location.pointer)};
-    additional_pointer.push_back("additionalProperties");
-
-    additional =
-        IRObjectValue{{.pointer = std::move(additional_pointer)}, false, false};
+    const auto &additional_schema{subschema.at("additionalProperties")};
+    const auto is_false{additional_schema.is_boolean() &&
+                        !additional_schema.to_boolean()};
+    if (!is_false) {
+      auto additional_pointer{sourcemeta::core::to_pointer(location.pointer)};
+      additional_pointer.push_back("additionalProperties");
+      additional = IRType{.pointer = std::move(additional_pointer)};
+    }
   }
 
   return IRObject{{.pointer = sourcemeta::core::to_pointer(location.pointer)},

test/e2e/typescript/2020-12/additional_properties_false/expected.d.ts

@@ -0,0 +1,10 @@
+export type StrictPerson_Properties_Name = string;
+
+export type StrictPerson_Properties_Age = number;
+
+export type StrictPerson_AdditionalProperties = never;
+
+export interface StrictPerson {
+  "name": StrictPerson_Properties_Name;
+  "age"?: StrictPerson_Properties_Age;
+}

test/e2e/typescript/2020-12/additional_properties_false/options.json

@@ -0,0 +1,3 @@
+{
+  "defaultPrefix": "StrictPerson"
+}

test/e2e/typescript/2020-12/additional_properties_false/schema.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "type": "object",
+  "properties": {
+    "name": {
+      "type": "string"
+    },
+    "age": {
+      "type": "integer"
+    }
+  },
+  "required": [ "name" ],
+  "additionalProperties": false
+}

test/e2e/typescript/2020-12/additional_properties_false/test.ts

@@ -0,0 +1,73 @@
+import { StrictPerson } from "./expected";
+
+// Valid: required name only
+const person1: StrictPerson = {
+  name: "John Doe"
+};
+
+// Valid: name and optional age
+const person2: StrictPerson = {
+  name: "Jane Doe",
+  age: 25
+};
+
+// Invalid: name must be string
+const person3: StrictPerson = {
+  // @ts-expect-error
+  name: 123
+};
+
+// Invalid: age must be number
+const person4: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  age: "twenty"
+};
+
+// Invalid: missing required name
+// @ts-expect-error
+const person5: StrictPerson = {
+  age: 30
+};
+
+// Invalid: extra string property should be rejected
+const person6: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  nickname: "Johnny"
+};
+
+// Invalid: extra number property should be rejected
+const person7: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  score: 100
+};
+
+// Invalid: extra boolean property should be rejected
+const person8: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  active: true
+};
+
+// Invalid: extra null property should be rejected
+const person9: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  nothing: null
+};
+
+// Invalid: extra array property should be rejected
+const person10: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  tags: [ "a", "b" ]
+};
+
+// Invalid: extra object property should be rejected
+const person11: StrictPerson = {
+  name: "John",
+  // @ts-expect-error
+  metadata: { foo: "bar" }
+};

test/e2e/typescript/2020-12/additional_properties_true/expected.d.ts

@@ -0,0 +1,34 @@
+export type FlexibleRecord_Properties_Name = string;
+
+export type FlexibleRecord_Properties_Count = number;
+
+export type FlexibleRecord_AdditionalProperties_AnyOf_ZIndex5 = number;
+
+export type FlexibleRecord_AdditionalProperties_AnyOf_ZIndex4 = string;
+
+export type FlexibleRecord_AdditionalProperties_AnyOf_ZIndex3 = unknown[];
+
+export interface FlexibleRecord_AdditionalProperties_AnyOf_ZIndex2 {
+}
+
+export type FlexibleRecord_AdditionalProperties_AnyOf_ZIndex1 = boolean;
+
+export type FlexibleRecord_AdditionalProperties_AnyOf_ZIndex0 = null;
+
+export type FlexibleRecord_AdditionalProperties =
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex0 |
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex1 |
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex2 |
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex3 |
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex4 |
+  FlexibleRecord_AdditionalProperties_AnyOf_ZIndex5;
+
+export interface FlexibleRecord {
+  "name": FlexibleRecord_Properties_Name;
+  "count"?: FlexibleRecord_Properties_Count;
+  [key: string]:
+    FlexibleRecord_Properties_Name |
+    FlexibleRecord_Properties_Count |
+    FlexibleRecord_AdditionalProperties |
+    undefined;
+}

test/e2e/typescript/2020-12/additional_properties_true/options.json

@@ -0,0 +1,3 @@
+{
+  "defaultPrefix": "FlexibleRecord"
+}

test/e2e/typescript/2020-12/additional_properties_true/schema.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "type": "object",
+  "properties": {
+    "name": {
+      "type": "string"
+    },
+    "count": {
+      "type": "integer"
+    }
+  },
+  "required": [ "name" ],
+  "additionalProperties": true
+}