support enum without a type field (#83)

* closes: #79 issue with singleton enum

* closes: #82 support enum without type

* closes: #82 support enum without type

Author: massfords

.changeset/cyan-tables-fetch.md

@@ -0,0 +1,5 @@
+---
+"typed-openapi": patch
+---
+
+closes: #82 by supporting enum without type

packages/typed-openapi/src/openapi-schema-to-ts.ts

@@ -94,6 +94,18 @@ export const openApiSchemaToTs = ({ schema, meta: _inheritedMeta, ctx }: Openapi
       if (schemaType === "number" || schemaType === "integer") return t.number();
       if (schemaType === "null") return t.literal("null");
     }
+    if (!schemaType && schema.enum) {
+      return t.union(schema.enum.map((value) => {
+        if (typeof value === "string") {
+          return t.literal(`"${value}"`)
+        }
+        if (value === null) {
+          return t.literal("null")
+        }
+        // handle boolean and number literals
+        return t.literal(value)
+      }));
+    }
 
     if (schemaType === "array") {
       if (schema.items) {

packages/typed-openapi/tests/openapi-schema-to-ts.test.ts

@@ -365,6 +365,16 @@ test("getSchemaBox", () => {
     }
   `);
 
+  expect(getSchemaBox({ enum: ["red", "amber", "green", null, 42, true] })).toMatchInlineSnapshot(
+    `
+    {
+      "type": "union",
+      "value": "("red" | "amber" | "green" | null | 42 | true)",
+    }
+  `,
+  );
+
+
   expect(getSchemaBox({
     "type": "object",
     "properties": {