From c5e839314069598f65d00bba57c14b33ae0c431f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20T=C3=B8mmer=C3=A5s?= <flugged@gmail.com>
Date: Wed, 21 Dec 2022 16:07:36 +0100
Subject: [PATCH] feat: support conditionals in mapped types (#1510)

Co-authored-by: Dominik Moritz <domoritz@gmail.com>
fixes https://github.com/vega/ts-json-schema-generator/issues/1502
---
 src/NodeParser/MappedTypeNodeParser.ts        | 12 +++++-----
 test/valid-data-type.test.ts                  |  1 +
 .../main.ts                                   |  9 ++++++++
 .../schema.json                               | 22 +++++++++++++++++++
 4 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 test/valid-data/type-mapped-index-as-with-conditional/main.ts
 create mode 100644 test/valid-data/type-mapped-index-as-with-conditional/schema.json

diff --git a/src/NodeParser/MappedTypeNodeParser.ts b/src/NodeParser/MappedTypeNodeParser.ts
index ef0331db2..ac9c7862f 100644
--- a/src/NodeParser/MappedTypeNodeParser.ts
+++ b/src/NodeParser/MappedTypeNodeParser.ts
@@ -13,7 +13,6 @@ import { ObjectProperty, ObjectType } from "../Type/ObjectType";
 import { StringType } from "../Type/StringType";
 import { SymbolType } from "../Type/SymbolType";
 import { UnionType } from "../Type/UnionType";
-import assert from "../Utils/assert";
 import { derefAnnotatedType, derefType } from "../Utils/derefType";
 import { getKey } from "../Utils/nodeKey";
 import { preserveAnnotation } from "../Utils/preserveAnnotation";
@@ -79,14 +78,14 @@ export class MappedTypeNodeParser implements SubNodeParser {
         }
     }
 
-    protected mapKey(node: ts.MappedTypeNode, rawKey: LiteralType, context: Context): LiteralType {
+    protected mapKey(node: ts.MappedTypeNode, rawKey: LiteralType, context: Context): BaseType {
         if (!node.nameType) {
             return rawKey;
         }
         const key = derefType(
             this.childNodeParser.createType(node.nameType, this.createSubContext(node, rawKey, context))
         );
-        assert(key instanceof LiteralType, "Must resolve to Literal");
+
         return key;
     }
 
@@ -94,8 +93,9 @@ export class MappedTypeNodeParser implements SubNodeParser {
         return keyListType
             .getTypes()
             .filter((type): type is LiteralType => type instanceof LiteralType)
-            .reduce((result: ObjectProperty[], key: LiteralType) => {
-                const namedKey = this.mapKey(node, key, context);
+            .map((type) => [type, this.mapKey(node, type, context)])
+            .filter((value): value is [LiteralType, LiteralType] => value[1] instanceof LiteralType)
+            .reduce((result: ObjectProperty[], [key, mappedKey]: [LiteralType, LiteralType]) => {
                 const propertyType = this.childNodeParser.createType(
                     node.type!,
                     this.createSubContext(node, key, context)
@@ -110,7 +110,7 @@ export class MappedTypeNodeParser implements SubNodeParser {
                 }
 
                 const objectProperty = new ObjectProperty(
-                    namedKey.getValue().toString(),
+                    mappedKey.getValue().toString(),
                     preserveAnnotation(propertyType, newType),
                     !node.questionToken && !hasUndefined
                 );
diff --git a/test/valid-data-type.test.ts b/test/valid-data-type.test.ts
index 44c969374..329ea0935 100644
--- a/test/valid-data-type.test.ts
+++ b/test/valid-data-type.test.ts
@@ -89,6 +89,7 @@ describe("valid-data-type", () => {
     it("type-mapped-index", assertValidSchema("type-mapped-index", "MyObject"));
     it("type-mapped-index-as", assertValidSchema("type-mapped-index-as", "MyObject"));
     it("type-mapped-index-as-template", assertValidSchema("type-mapped-index-as-template", "MyObject"));
+    it("type-mapped-index-as-with-conditional", assertValidSchema("type-mapped-index-as-with-conditional", "MyObject"));
     it("type-mapped-literal", assertValidSchema("type-mapped-literal", "MyObject"));
     it("type-mapped-generic", assertValidSchema("type-mapped-generic", "MyObject"));
     it("type-mapped-native", assertValidSchema("type-mapped-native", "MyObject"));
diff --git a/test/valid-data/type-mapped-index-as-with-conditional/main.ts b/test/valid-data/type-mapped-index-as-with-conditional/main.ts
new file mode 100644
index 000000000..296978409
--- /dev/null
+++ b/test/valid-data/type-mapped-index-as-with-conditional/main.ts
@@ -0,0 +1,9 @@
+interface Message {
+    id: number;
+    name: string;
+    title: string;
+}
+
+export type MyObject = {
+    [K in keyof Message as Exclude<K, "title">]: Message[K];
+};
diff --git a/test/valid-data/type-mapped-index-as-with-conditional/schema.json b/test/valid-data/type-mapped-index-as-with-conditional/schema.json
new file mode 100644
index 000000000..2f4d9703c
--- /dev/null
+++ b/test/valid-data/type-mapped-index-as-with-conditional/schema.json
@@ -0,0 +1,22 @@
+{
+  "$ref": "#/definitions/MyObject",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "MyObject": {
+      "additionalProperties": false,
+      "properties": {
+        "id": {
+          "type": "number"
+        },
+        "name": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "id",
+        "name"
+      ],
+      "type": "object"
+    }
+  }
+}