add support for @save in api.ts file

changelog.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add support for `@save` in `api.ts` ([#89](https://github.com/hasura/ndc-open-api-lambda/pull/89))
+
 ## [[1.5.2](https://github.com/hasura/ndc-open-api-lambda/releases/tag/v1.5.2)] 2025-03-25
 
 - Update dependencies. Also update ndc-nodejs-lambda to `v1.12.0` ([#87](https://github.com/hasura/ndc-open-api-lambda/pull/87))

docs/documentation.md

@@ -66,15 +66,15 @@ const api = new Api({
 
 ## Saving User Changes
 
-When re-introspecting the connector, user changes in `functions.ts` can be preserved by adding an `@save` JS Doc Tag to the documentation comment of a statement. `@save` is currently supported for the following statements:
+When re-introspecting the connector, user changes in `functions.ts` or `api.ts` can be preserved by adding an `@save` JS Doc Tag to the documentation comment of a statement. `@save` is only supported for root level statements. `@save` is currently supported for the following statements:
 
 - functions
 - variable/constant declarations
 - types
 - interfaces
 - classes
 
-This will ensure that the statements marked with `@save` are not overwritten and the saved statements will be added if missing in the newly generated `functions.ts`
+This will ensure that the statements marked with `@save` are not overwritten and the saved statements will be added if missing in the newly generated `functions.ts` or the `apt.ts` file
 
 Example
 

src/app/writer/api-ts-writer.ts

@@ -1,6 +1,8 @@
 import * as types from "../types";
 import * as fs from "fs";
 import * as logger from "../../util/logger";
+import * as tsParser from "../parser/typescript";
+import * as format from "../parser/typescript/fomat";
 
 export class SimilarFileContentsError extends Error {
   constructor(message: string) {
@@ -9,22 +11,27 @@ export class SimilarFileContentsError extends Error {
   }
 }
 
-export function writeToFileSystem(codeToWrite: types.GeneratedCode) {
+export async function writeToFileSystem(codeToWrite: types.GeneratedCode) {
   if (!fs.existsSync(codeToWrite.filePath)) {
     logger.info(`Creating ${codeToWrite.filePath}`);
     fs.writeFileSync(codeToWrite.filePath, codeToWrite.fileContent);
     return;
   }
 
   const staleFile = fs.readFileSync(codeToWrite.filePath).toString();
-  const shouldOverwrite = staleFile !== codeToWrite.fileContent;
-
-  if (!shouldOverwrite) {
-    throw new SimilarFileContentsError(
-      `'${codeToWrite.filePath}' already represents the latest OpenAPI Document`,
-    );
-  }
 
   logger.info(`Overwriting ${codeToWrite.filePath}`);
+
+  codeToWrite.fileContent = tsParser.preserveUserChanges(
+    staleFile,
+    codeToWrite.fileContent,
+  );
+
+  await cleanupAndFormat(codeToWrite);
+
   fs.writeFileSync(codeToWrite.filePath, codeToWrite.fileContent);
 }
+
+export async function cleanupAndFormat(apiTs: types.GeneratedCode) {
+  apiTs.fileContent = await format.format(apiTs.fileContent);
+}

src/app/writer/index.ts

@@ -16,7 +16,7 @@ export async function writeToFileSystem(codeToWrite: types.GeneratedCode[]) {
       (element) => element.fileType === "functions-ts",
     )[0]!;
 
-    apiWriter.writeToFileSystem(apiTsCode);
+    await apiWriter.writeToFileSystem(apiTsCode);
     await functionsWriter.writeToFileSystem(functionsTsCode, apiTsCode);
     await packageJsonWriter.writeToFileSystem();
     tsConfigWriter.writeToFileSystem();