Integrated feedback from @freben

Signed-off-by: Taras <tarasm@gmail.com>

.changeset/large-books-deny.md

@@ -2,4 +2,4 @@
 '@backstage/catalog-client': minor
 ---
 
-Adding validateEntity method that calls /validate-entity endpoint
+Adding `validateEntity` method that calls `/validate-entity` endpoint.

packages/catalog-client/api-report.md

@@ -209,8 +209,12 @@ type Location_2 = {
 export { Location_2 as Location };
 
 // @public
-export type ValidateEntityResponse = {
-  valid: boolean;
-  errors?: SerializedError[];
-};
+export type ValidateEntityResponse =
+  | {
+      valid: true;
+    }
+  | {
+      valid: false;
+      errors: SerializedError[];
+    };
 ```

packages/catalog-client/src/CatalogClient.ts

@@ -21,7 +21,7 @@ import {
   stringifyEntityRef,
   stringifyLocationRef,
 } from '@backstage/catalog-model';
-import { ResponseError, SerializedError } from '@backstage/errors';
+import { ResponseError } from '@backstage/errors';
 import crossFetch from 'cross-fetch';
 import {
   CATALOG_FILTER_EXISTS,
@@ -377,11 +377,14 @@ export class CatalogClient implements CatalogApi {
     if (response.ok) {
       return {
         valid: true,
-        errors: undefined,
       };
     }
 
-    const { errors } = (await response.json()) as { errors: SerializedError[] };
+    if (response.status !== 400) {
+      throw await ResponseError.fromResponse(response);
+    }
+
+    const { errors = [] } = await response.json();
 
     return {
       valid: false,

packages/catalog-client/src/types/api.ts

@@ -275,10 +275,9 @@ export type AddLocationResponse = {
  *
  * @public
  */
-export type ValidateEntityResponse = {
-  valid: boolean;
-  errors?: SerializedError[];
-};
+export type ValidateEntityResponse =
+  | { valid: true }
+  | { valid: false; errors: SerializedError[] };
 
 /**
  * A client for interacting with the Backstage software catalog through its API.