Merge pull request #14506 from Automattic/IslandRhythms/list-databases

feat: `listDatabases()` function

Author: vkarpov15

lib/connection.js

@@ -647,6 +647,30 @@ Connection.prototype.listCollections = async function listCollections() {
   return await cursor.toArray();
 };
 
+/**
+ * Helper for MongoDB Node driver's `listDatabases()`.
+ * Returns an object with a `databases` property that contains an
+ * array of database objects.
+ *
+ * #### Example:
+ *     const { databases } = await mongoose.connection.listDatabases();
+ *     databases; // [{ name: 'mongoose_test', sizeOnDisk: 0, empty: false }]
+ *
+ * @method listCollections
+ * @return {Promise<{ databases: Array<{ name: string }> }>}
+ * @api public
+ */
+
+Connection.prototype.listDatabases = async function listDatabases() {
+  if ((this.readyState === STATES.connecting || this.readyState === STATES.disconnected) && this._shouldBufferCommands()) {
+    await new Promise(resolve => {
+      this._queue.push({ fn: resolve });
+    });
+  }
+
+  return await this.db.admin().listDatabases();
+};
+
 /**
  * Helper for `dropDatabase()`. Deletes the given database, including all
  * collections, documents, and indexes.

test/connection.test.js

@@ -1580,6 +1580,17 @@ describe('connections:', function() {
     });
     assert.ok(session);
   });
+  it('listDatabases() should return a list of database objects with a name property (gh-9048)', async function() {
+    const connection = await mongoose.createConnection(start.uri).asPromise();
+    // If this test is running in isolation, then the `start.uri` db might not
+    // exist yet, so create this collection (and the associated db) just in case
+    await connection.createCollection('tests').catch(() => {});
+
+    const { databases } = await connection.listDatabases();
+    assert.ok(connection.name);
+    console.log(databases);
+    assert.ok(databases.map(database => database.name).includes(connection.name));
+  });
   describe('createCollections()', function() {
     it('should create collections for all models on the connection with the createCollections() function (gh-13300)', async function() {
       const m = new mongoose.Mongoose();

test/types/connection.test.ts

@@ -78,6 +78,10 @@ expectType<Promise<string[]>>(
   conn.listCollections().then(collections => collections.map(coll => coll.name))
 );
 
+expectType<Promise<string[]>>(
+  conn.listDatabases().then(dbs => dbs.databases.map(db => db.name))
+);
+
 export function autoTypedModelConnection() {
   const AutoTypedSchema = autoTypedSchema();
   const AutoTypedModel = connection.model('AutoTypeModelConnection', AutoTypedSchema);

types/connection.d.ts

@@ -132,6 +132,12 @@ declare module 'mongoose' {
      */
     listCollections(): Promise<Pick<mongodb.CollectionInfo, 'name' | 'type'>[]>;
 
+    /**
+     * Helper for MongoDB Node driver's `listDatabases()`.
+     * Returns an array of database names.
+     */
+    listDatabases(): Promise<mongodb.ListDatabasesResult>;
+
     /**
      * A [POJO](https://masteringjs.io/tutorials/fundamentals/pojo) containing
      * a map from model names to models. Contains all models that have been