Extract pluralize method

There are at least 4 different files where this method could DRY things up,
so let's extract it.

I've chosen to move it to src/helpers.ts but happy to be told there's a better
place for shared utility methods like this one.

Author: elenatanasoiu

extensions/ql-vscode/src/helpers.ts

@@ -581,3 +581,11 @@ export async function* walkDirectory(dir: string): AsyncIterableIterator<string>
     }
   }
 }
+
+/**
+ * Pluralizes a word.
+ * Example: Returns "N repository" if N is one, "N repositories" otherwise.
+ */
+export function pluralize(numItems: number | undefined, singular: string, plural: string): string {
+  return numItems ? `${numItems} ${numItems === 1 ? singular : plural}` : '';
+}

extensions/ql-vscode/src/remote-queries/run-remote-query.ts

@@ -11,6 +11,7 @@ import {
   showAndLogErrorMessage,
   showAndLogInformationMessage,
   tryGetQueryMetadata,
+  pluralize,
   tmpDir
 } from '../helpers';
 import { Credentials } from '../authentication';
@@ -352,44 +353,37 @@ async function runRemoteQueriesApiRequest(
 const eol = os.EOL;
 const eol2 = os.EOL + os.EOL;
 
-/**
- * Returns "N repository" if N is one, "N repositories" otherwise.
- */
-function pluralizeRepositories(numRepositories: number) {
-  return `${numRepositories} ${numRepositories === 1 ? 'repository' : 'repositories'}`;
-}
-
 // exported for testing only
 export function parseResponse(owner: string, repo: string, response: QueriesResponse) {
   const repositoriesQueried = response.repositories_queried;
   const numRepositoriesQueried = repositoriesQueried.length;
 
-  const popupMessage = `Successfully scheduled runs on ${pluralizeRepositories(numRepositoriesQueried)}. [Click here to see the progress](https://github.com/${owner}/${repo}/actions/runs/${response.workflow_run_id}).`
+  const popupMessage = `Successfully scheduled runs on ${pluralize(numRepositoriesQueried, 'repository', 'repositories')}. [Click here to see the progress](https://github.com/${owner}/${repo}/actions/runs/${response.workflow_run_id}).`
     + (response.errors ? `${eol2}Some repositories could not be scheduled. See extension log for details.` : '');
 
-  let logMessage = `Successfully scheduled runs on ${pluralizeRepositories(numRepositoriesQueried)}. See https://github.com/${owner}/${repo}/actions/runs/${response.workflow_run_id}.`;
+  let logMessage = `Successfully scheduled runs on ${pluralize(numRepositoriesQueried, 'repository', 'repositories')}. See https://github.com/${owner}/${repo}/actions/runs/${response.workflow_run_id}.`;
   logMessage += `${eol2}Repositories queried:${eol}${repositoriesQueried.join(', ')}`;
   if (response.errors) {
     const { invalid_repositories, repositories_without_database, private_repositories, cutoff_repositories, cutoff_repositories_count } = response.errors;
     logMessage += `${eol2}Some repositories could not be scheduled.`;
     if (invalid_repositories?.length) {
-      logMessage += `${eol2}${pluralizeRepositories(invalid_repositories.length)} invalid and could not be found:${eol}${invalid_repositories.join(', ')}`;
+      logMessage += `${eol2}${pluralize(invalid_repositories.length, 'repository', 'repositories')} invalid and could not be found:${eol}${invalid_repositories.join(', ')}`;
     }
     if (repositories_without_database?.length) {
-      logMessage += `${eol2}${pluralizeRepositories(repositories_without_database.length)} did not have a CodeQL database available:${eol}${repositories_without_database.join(', ')}`;
+      logMessage += `${eol2}${pluralize(repositories_without_database.length, 'repository', 'repositories')} did not have a CodeQL database available:${eol}${repositories_without_database.join(', ')}`;
       logMessage += `${eol}For each public repository that has not yet been added to the database service, we will try to create a database next time the store is updated.`;
     }
     if (private_repositories?.length) {
-      logMessage += `${eol2}${pluralizeRepositories(private_repositories.length)} not public:${eol}${private_repositories.join(', ')}`;
+      logMessage += `${eol2}${pluralize(private_repositories.length, 'repository', 'repositories')} not public:${eol}${private_repositories.join(', ')}`;
       logMessage += `${eol}When using a public controller repository, only public repositories can be queried.`;
     }
     if (cutoff_repositories_count) {
-      logMessage += `${eol2}${pluralizeRepositories(cutoff_repositories_count)} over the limit for a single request`;
+      logMessage += `${eol2}${pluralize(cutoff_repositories_count, 'repository', 'repositories')} over the limit for a single request`;
       if (cutoff_repositories) {
         logMessage += `:${eol}${cutoff_repositories.join(', ')}`;
         if (cutoff_repositories_count !== cutoff_repositories.length) {
           const moreRepositories = cutoff_repositories_count - cutoff_repositories.length;
-          logMessage += `${eol}...${eol}And another ${pluralizeRepositories(moreRepositories)}.`;
+          logMessage += `${eol}...${eol}And another ${pluralize(moreRepositories, 'repository', 'repositories')}.`;
         }
       } else {
         logMessage += '.';