fix(openapi-typescript): Stringify primitive constant values (#1149)

* fix(openapi-typescript): Stringify primitive constant values

Closes #1118

* fixup! fix(openapi-typescript): Stringify primitive constant

Author: duncanbeevers

.changeset/eighty-chairs-join.md

@@ -0,0 +1,5 @@
+---
+"openapi-typescript": minor
+---
+
+Stringify const values with no specified type

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

@@ -41,13 +41,7 @@ export function defaultSchemaObjectTransform(schemaObject: SchemaObject | Refere
 
   // const (valid for any type)
   if (schemaObject.const !== null && schemaObject.const !== undefined) {
-    let schemaConst = schemaObject.const as any;
-    if ("type" in schemaObject) {
-      if (schemaObject.type === "string") {
-        schemaConst = escStr(schemaConst);
-      }
-    }
-    return transformSchemaObject(schemaConst, {
+    return transformSchemaObject(escStr(schemaObject.const) as any, {
       path,
       ctx: { ...ctx, immutableTypes: false, indentLv: indentLv + 1 }, // note: guarantee readonly happens once, here
     });

packages/openapi-typescript/src/utils.ts

@@ -257,7 +257,7 @@ export function tsUnionOf(...types: (string | number | boolean)[]): string {
 
 /** escape string value */
 export function escStr(input: any): string {
-  if (typeof input !== "string") return input;
+  if (typeof input !== "string") return JSON.stringify(input);
   return `"${input.trim().replace(DOUBLE_QUOTE_RE, '\\"')}"`;
 }
 

packages/openapi-typescript/test/schema-object.test.ts

@@ -255,6 +255,21 @@ describe("Schema Object", () => {
         const generated = transformSchemaObject({ type: "string", const: "duck" }, options);
         expect(generated).toBe(`"duck"`);
       });
+
+      test("number", () => {
+        const generated = transformSchemaObject({ type: "number", const: 42 }, options);
+        expect(generated).toBe("42");
+      });
+
+      test("string, no type specified", () => {
+        const generated = transformSchemaObject({ const: "99" }, options);
+        expect(generated).toBe(`"99"`);
+      });
+
+      test("number, no type specified", () => {
+        const generated = transformSchemaObject({ const: 300 }, options);
+        expect(generated).toBe("300");
+      });
     });
 
     describe("polymorphic", () => {