feat(common): add OpenAPI spec exporter utility function

This will be useful to reuse among the individual packages
own openapi-spec.ts files which at the
moment
all repeat the same logic to export themselves to JSON...

Signed-off-by: Peter Somogyvari <peter.somogyvari@accenture.com>

packages/cactus-common/package.json

@@ -74,6 +74,7 @@
   "devDependencies": {
     "@types/joi": "14.3.4",
     "@types/json-stable-stringify": "1.0.32",
-    "@types/secp256k1": "4.0.1"
+    "@types/secp256k1": "4.0.1",
+    "openapi-types": "7.0.1"
   }
-}
+}

packages/cactus-common/src/main/typescript/index.ts

@@ -1,2 +1,8 @@
 export * from "./public-api";
 export { IListenOptions, Servers } from "./servers";
+export {
+  DEFAULT_FILENAME,
+  DEFAULT_RELATIVE_PATH,
+  IOpenApiSpecJsonToFsOptions,
+  openApiSpecJsonToFs,
+} from "./nodejs/openapi-spec-json-to-fs";

packages/cactus-common/src/main/typescript/nodejs/openapi-spec-json-to-fs.ts

@@ -0,0 +1,51 @@
+import { OpenAPIV3 } from "openapi-types";
+
+/**
+ * Options to customize how the `openApiSpecJsonToFs()` function exports
+ * an OpenAPI spec to JSON format to the local file-system.
+ */
+export interface IOpenApiSpecJsonToFsOptions {
+  /**
+   * The actual specification document (object) that holds the information we
+   * will export to JSON onto the local filesystem.
+   */
+  openApiSpec: OpenAPIV3.Document;
+  /**
+   * Absolute path on the file-system for the calling script file
+   * (e.g. `__dirname` in a NodeJS environment).
+   */
+  callerScriptPath: string;
+  /**
+   * Defaults to "../json/generated/"
+   */
+  relativePath?: string;
+  /**
+   * The target filename to export the JSON created from the OpenAPI spec.
+   * Defaults to "openapi-spec.json"
+   */
+  filename?: string;
+}
+
+export const DEFAULT_RELATIVE_PATH: string = "../json/generated/";
+
+export const DEFAULT_FILENAME: string = "openapi-spec.json";
+
+export async function openApiSpecJsonToFs(
+  opts: IOpenApiSpecJsonToFsOptions
+): Promise<void> {
+  const fnTag = "#openApiSpecJsonToFs()";
+
+  const fs = await import("fs");
+  const path = await import("path");
+
+  const filename = opts.filename || DEFAULT_FILENAME;
+  const relativePath = opts.relativePath || DEFAULT_RELATIVE_PATH;
+  const callerScriptPath = opts.callerScriptPath;
+  const defaultDest = path.join(callerScriptPath, relativePath, filename);
+  const destination = process.argv[2] || defaultDest;
+
+  // tslint:disable-next-line: no-console
+  console.log(`${fnTag} destination=${destination}`);
+
+  fs.writeFileSync(destination, JSON.stringify(opts.openApiSpec, null, 4));
+}