[RESTDataSource] refactor to allow overridding the Error class

for example if we want to create a `NotFoundError` that will be used when receiving 404s. This way we need to override the bare minimum like

```
class MyDataSource extends RESTDataSource {
  protected errorBaseFromResponseAndMessage(response: Response, message: string): ApolloError {
    if (response.status === 401) return new NotFoundError(message);

    return super.errorBaseFromResponseAndMessage(response, message);
  }
}
```

Also adding it in the RemoteGraphQLDataSource since it has the same code as RESTDataSource, for symmetry purposes.

Signed-off-by: Eduardo Turiño <[email protected]>

packages/apollo-datasource-rest/src/RESTDataSource.ts

@@ -125,17 +125,16 @@ export abstract class RESTDataSource<TContext = any> extends DataSource {
     }
   }
 
+  protected errorBaseFromResponseAndMessage(response: Response, message: string): ApolloError {
+    if (response.status === 401) return new AuthenticationError(message);
+    if (response.status === 403) return new ForbiddenError(message);
+    return new ApolloError(message);
+  }
+
   protected async errorFromResponse(response: Response) {
     const message = `${response.status}: ${response.statusText}`;
 
-    let error: ApolloError;
-    if (response.status === 401) {
-      error = new AuthenticationError(message);
-    } else if (response.status === 403) {
-      error = new ForbiddenError(message);
-    } else {
-      error = new ApolloError(message);
-    }
+    const error = this.errorBaseFromResponseAndMessage(response, message);
 
     const body = await this.parseBody(response);
 

packages/apollo-gateway/src/datasources/RemoteGraphQLDataSource.ts

@@ -200,17 +200,16 @@ export class RemoteGraphQLDataSource<TContext extends Record<string, any> = Reco
     }
   }
 
+  protected errorBaseFromResponseAndMessage(response: Response, message: string): ApolloError {
+    if (response.status === 401) return new AuthenticationError(message);
+    if (response.status === 403) return new ForbiddenError(message);
+    return new ApolloError(message);
+  }
+
   public async errorFromResponse(response: Response) {
     const message = `${response.status}: ${response.statusText}`;
 
-    let error: ApolloError;
-    if (response.status === 401) {
-      error = new AuthenticationError(message);
-    } else if (response.status === 403) {
-      error = new ForbiddenError(message);
-    } else {
-      error = new ApolloError(message);
-    }
+    const error = this.errorBaseFromResponseAndMessage(response, message);
 
     const body = await this.parseBody(response);