Escape constant string in generated schema (#1014)

* Escape strings in constants

* Adjust and extend test for constant string value

* Run prettier

Author: mvdbeek

src/transform/schema-object.ts

@@ -62,7 +62,13 @@ export function defaultSchemaObjectTransform(
 
   // const (valid for any type)
   if (schemaObject.const) {
-    return transformSchemaObject(schemaObject.const as any, {
+    let schemaConst = schemaObject.const as any;
+    if ("type" in schemaObject) {
+      if (schemaObject.type === "string") {
+        schemaConst = escStr(schemaConst)
+      }
+    }
+    return transformSchemaObject(schemaConst, {
       path,
       ctx: { ...ctx, immutableTypes: false, indentLv: indentLv + 1 }, // note: guarantee readonly happens once, here
     });

test/schema-object.test.ts

@@ -134,6 +134,19 @@ describe("Schema Object", () => {
 }`);
       });
 
+      test("const string field", () => {
+        const schema: SchemaObject = {
+          type: "object",
+          properties: { constant: { const: "a", type: "string" } },
+          required: ["constant"],
+        };
+        const generated = transformSchemaObject(schema, options);
+        expect(generated).toBe(`{
+  /** @constant */
+  constant: "a";
+}`);
+      });
+
       test("additionalProperties with properties", () => {
         const schema: SchemaObject = {
           type: "object",
@@ -186,7 +199,7 @@ describe("Schema Object", () => {
     describe("const", () => {
       test("string", () => {
         const generated = transformSchemaObject({ type: "string", const: "duck" }, options);
-        expect(generated).toBe("duck");
+        expect(generated).toBe(`"duck"`);
       });
     });