Add support for x-enum-varnames and x-enum-descriptions (#1374)

* Add support for x-enum-varnames and x-enum-descriptions

* Refactor ts enum members

.changeset/chilled-news-design.md

@@ -0,0 +1,5 @@
+---
+"openapi-typescript": minor
+---
+
+Add support for x-enum-varnames and x-enum-descriptions

docs/src/content/docs/advanced.md

@@ -521,3 +521,44 @@ Cat: { type?: "cat"; } & components["schemas"]["PetCommonProperties"];
 _Note: you optionally could provide `discriminator.propertyName: "type"` on `Pet` ([docs](https://spec.openapis.org/oas/v3.1.0#discriminator-object)) to automatically generate the `type` key, but is less explicit._
 
 While the schema permits you to use composition in any way you like, it’s good to always take a look at the generated types and see if there’s a simpler way to express your unions & intersections. Limiting the use of `oneOf` is not the only way to do that, but often yields the greatest benefits.
+
+### Enum with custom names and descriptions
+
+`x-enum-varnames` can be used to have another enum name for the corresponding value. This is used to define names of the enum items.
+
+`x-enum-descriptions` can be used to provide an individual description for each value. This is used for comments in the code (like javadoc if the target language is java).
+
+`x-enum-descriptions` and `x-enum-varnames` are each expected to be list of items containing the same number of items as enum. The order of the items in the list matters: their position is used to group them together.
+
+Example:
+
+```yaml
+ErrorCode:
+  type: integer
+  format: int32
+  enum:
+    - 100
+    - 200
+    - 300
+  x-enum-varnames:
+    - Unauthorized
+    - AccessDenied
+    - Unknown
+  x-enum-descriptions:
+    - "User is not authorized"
+    - "User has no access to this resource"
+    - "Something went wrong"
+```
+
+Will result in:
+
+```ts
+enum ErrorCode {
+  // User is not authorized
+  Unauthorized = 100
+  // User has no access to this resource
+  AccessDenied = 200
+  // Something went wrong
+  Unknown = 300
+}
+```

packages/openapi-typescript/src/lib/ts.ts

@@ -229,6 +229,7 @@ export function tsDedupe(types: ts.TypeNode[]): ts.TypeNode[] {
 export function tsEnum(
   name: string,
   members: (string | number)[],
+  metadata?: { name?: string; description?: string }[],
   options?: { readonly?: boolean; export?: boolean },
 ) {
   let enumName = name.replace(JS_ENUM_INVALID_CHARS_RE, (c) => {
@@ -249,28 +250,47 @@ export function tsEnum(
         })
       : undefined,
     /* name      */ enumName,
-    /* members   */ members.map(tsEnumMember),
+    /* members   */ members.map((value, i) =>
+      tsEnumMember(value, metadata?.[i]),
+    ),
   );
 }
 
 /** Sanitize TS enum member expression */
-export function tsEnumMember(value: string | number) {
-  if (typeof value === "number") {
-    return ts.factory.createEnumMember(
-      `Value${String(value)}`.replace(".", "_"), // don’t forget decimals
-      ts.factory.createNumericLiteral(value),
-    );
-  }
-  let name = value;
+export function tsEnumMember(
+  value: string | number,
+  metadata: { name?: string; description?: string } = {},
+) {
+  let name = metadata.name ?? String(value);
   if (!JS_PROPERTY_INDEX_RE.test(name)) {
     if (Number(name[0]) >= 0) {
-      name = `Value${name}`;
+      name = `Value${name}`.replace(".", "_"); // don't forged decimals;
     }
     name = name.replace(JS_PROPERTY_INDEX_INVALID_CHARS_RE, "_");
   }
-  return ts.factory.createEnumMember(
-    name,
-    ts.factory.createStringLiteral(value),
+
+  let member;
+  if (typeof value === "number") {
+    member = ts.factory.createEnumMember(
+      name,
+      ts.factory.createNumericLiteral(value),
+    );
+  } else {
+    member = ts.factory.createEnumMember(
+      name,
+      ts.factory.createStringLiteral(value),
+    );
+  }
+
+  if (metadata.description == undefined) {
+    return member;
+  }
+
+  return ts.addSyntheticLeadingComment(
+    member,
+    ts.SyntaxKind.SingleLineCommentTrivia,
+    " ".concat(metadata.description.trim()),
+    true,
   );
 }
 

packages/openapi-typescript/src/transform/schema-object.ts

@@ -124,9 +124,14 @@ export function transformSchemaObjectWithComposition(
       let enumName = parseRef(options.path ?? "").pointer.join("/");
       // allow #/components/schemas to have simpler names
       enumName = enumName.replace("components/schemas", "");
+      const metadata = schemaObject.enum.map((_, i) => ({
+        name: schemaObject["x-enum-varnames"]?.[i],
+        description: schemaObject["x-enum-descriptions"]?.[i],
+      }));
       const enumType = tsEnum(
         enumName,
         schemaObject.enum as (string | number)[],
+        metadata,
         { export: true, readonly: options.ctx.immutable },
       );
       options.ctx.injectFooter.push(enumType);

packages/openapi-typescript/test/lib/ts.test.ts

@@ -127,6 +127,111 @@ describe("tsEnum", () => {
     Value100 = 100,
     Value101 = 101,
     Value102 = 102
+}`);
+  });
+
+  it("number members with x-enum-descriptions", () => {
+    expect(
+      astToString(
+        tsEnum(
+          ".Error.code.",
+          [100, 101, 102],
+          [
+            { description: "Code 100" },
+            { description: "Code 101" },
+            { description: "Code 102" },
+          ],
+        ),
+      ).trim(),
+    ).toBe(`enum ErrorCode {
+    // Code 100
+    Value100 = 100,
+    // Code 101
+    Value101 = 101,
+    // Code 102
+    Value102 = 102
+}`);
+  });
+
+  it("x-enum-varnames", () => {
+    expect(
+      astToString(
+        tsEnum(
+          ".Error.code.",
+          [100, 101, 102],
+          [
+            { name: "Unauthorized" },
+            { name: "NotFound" },
+            { name: "PermissionDenied" },
+          ],
+        ),
+      ).trim(),
+    ).toBe(`enum ErrorCode {
+    Unauthorized = 100,
+    NotFound = 101,
+    PermissionDenied = 102
+}`);
+  });
+
+  it("x-enum-varnames with numeric prefix", () => {
+    expect(
+      astToString(
+        tsEnum(
+          ".Error.code.",
+          [100, 101, 102],
+          [{ name: "0a" }, { name: "1b" }, { name: "2c" }],
+        ),
+      ).trim(),
+    ).toBe(`enum ErrorCode {
+    Value0a = 100,
+    Value1b = 101,
+    Value2c = 102
+}`);
+  });
+
+  it("partial x-enum-varnames and x-enum-descriptions", () => {
+    expect(
+      astToString(
+        tsEnum(
+          ".Error.code.",
+          [100, 101, 102],
+          [
+            { name: "Unauthorized", description: "User is unauthorized" },
+            { name: "NotFound" },
+          ],
+        ),
+      ).trim(),
+    ).toBe(`enum ErrorCode {
+    // User is unauthorized
+    Unauthorized = 100,
+    NotFound = 101,
+    Value102 = 102
+}`);
+  });
+
+  it("x-enum-descriptions with x-enum-varnames", () => {
+    expect(
+      astToString(
+        tsEnum(
+          ".Error.code.",
+          [100, 101, 102],
+          [
+            { name: "Unauthorized", description: "User is unauthorized" },
+            { name: "NotFound", description: "Item not found" },
+            {
+              name: "PermissionDenied",
+              description: "User doesn't have permissions",
+            },
+          ],
+        ),
+      ).trim(),
+    ).toBe(`enum ErrorCode {
+    // User is unauthorized
+    Unauthorized = 100,
+    // Item not found
+    NotFound = 101,
+    // User doesn't have permissions
+    PermissionDenied = 102
 }`);
   });
 });