feat: add function to find tsconfig.json

src/common.ts

@@ -13,9 +13,11 @@
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
 import {Logger} from '@openstapps/logger';
-import {mkdir, PathLike, readFile, unlink, writeFile} from 'fs';
+import {existsSync, mkdir, PathLike, readFile, unlink, writeFile} from 'fs';
 import * as glob from 'glob';
 import {Schema as JSONSchema, ValidationError} from 'jsonschema';
+import {platform} from 'os';
+import {join, sep} from 'path';
 import {Definition} from 'ts-json-schema-generator';
 import {Application, ProjectReflection} from 'typedoc';
 import {promisify} from 'util';
@@ -154,3 +156,31 @@ export function isSchemaWithDefinitions(schema: JSONSchema): schema is SchemaWit
 export function isThingWithType(thing: any): thing is { type: string } {
   return typeof thing.type === 'string';
 }
+
+/**
+ * Get path that contains a tsconfig.json
+ *
+ * @param startPath Path from where to start searching "upwards"
+ */
+export function getTsconfigPath(startPath: string): string {
+  let tsconfigPath = startPath;
+
+  // see https://stackoverflow.com/questions/9652043/identifying-the-file-system-root-with-node-js
+  const root = (platform() === 'win32') ? process.cwd().split(sep)[0] : '/';
+
+  // repeat until a tsconfig.json is found
+  while (!existsSync(join(tsconfigPath, 'tsconfig.json'))) {
+    if (tsconfigPath === root) {
+      throw new Error(`Reached file system root ${root} while searching for 'tsconfig.json' in ${startPath}!`);
+    }
+
+    // pop last directory
+    const tsconfigPathParts = tsconfigPath.split(sep);
+    tsconfigPathParts.pop();
+    tsconfigPath = tsconfigPathParts.join(sep);
+  }
+
+  logger.info(`Using 'tsconfig.json' from ${tsconfigPath}.`);
+
+  return tsconfigPath;
+}