feat(shell-api): add mongo.getDBs() and .getDBNames() MONGOSH-766

packages/i18n/src/locales/en_US.ts

@@ -1660,6 +1660,15 @@ const translations: Catalog = {
               link: 'https://docs.mongodb.com/manual/reference/method/Mongo.getDB',
               description: 'Returns the specified Database of the Mongo object.'
             },
+            getDBs: {
+              link: 'https://docs.mongodb.com/manual/reference/method/Mongo.getDBs',
+              description: 'Returns information about all databases. Uses the listDatabases command.'
+            },
+            getDBNames: {
+              link: 'https://docs.mongodb.com/manual/reference/method/Mongo.getDBs',
+              description: 'Returns an array of all database names. Uses the listDatabases command.',
+              example: 'db.getMongo().getDBNames().map(name => db.getSiblingDB(name).getCollectionNames())'
+            },
             connect: {
               link: 'https://docs.mongodb.com/manual/reference/method/connect',
               description: 'Creates a connection to a MongoDB instance and returns the reference to the database.'

packages/shell-api/src/integration.spec.ts

@@ -1744,6 +1744,18 @@ describe('Shell API (integration)', function() {
         expect(internalState.mongos).to.deep.equal([mongo]);
       });
     });
+    describe('getDBs', () => {
+      it('lists all databases', async() => {
+        const result = await mongo.getDBs();
+        expect(result.ok).to.equal(1);
+        expect(result.databases.find(db => db.name === 'admin').sizeOnDisk).to.be.a('number');
+      });
+    });
+    describe('getDBNames', () => {
+      it('lists all database names', async() => {
+        expect(await mongo.getDBNames()).to.include('admin');
+      });
+    });
   });
   describe('PlanCache', () => {
     describe('list', () => {

packages/shell-api/src/mongo.ts

@@ -218,21 +218,21 @@ export default class Mongo extends ShellApiClass {
     return `switched to db ${db}`;
   }
 
-  async _listDatabases(opts: ListDatabasesOptions = {}): Promise<{name: string, sizeOnDisk: number, empty: boolean}[]> {
+  async _listDatabases(opts: ListDatabasesOptions = {}): Promise<{ databases: {name: string, sizeOnDisk: number, empty: boolean}[] }> {
     const result = await this._serviceProvider.listDatabases('admin', { ...opts });
     if (!('databases' in result)) {
       const err = new MongoshRuntimeError('Got invalid result from "listDatabases"', CommonErrors.CommandFailed);
       this._internalState.messageBus.emit('mongosh:error', err);
       throw err;
     }
     this._cachedDatabaseNames = result.databases.map((db: any) => db.name);
-    return result.databases;
+    return result as any;
   }
 
   async _getDatabaseNamesForCompletion(): Promise<string[]> {
     return await Promise.race([
       (async() => {
-        return (await this._listDatabases({ readPreference: 'primaryPreferred' })).map(db => db.name);
+        return (await this._listDatabases({ readPreference: 'primaryPreferred' })).databases.map(db => db.name);
       })(),
       (async() => {
         // See the comment in _getCollectionNamesForCompletion/database.ts
@@ -243,14 +243,26 @@ export default class Mongo extends ShellApiClass {
     ]);
   }
 
+  @returnsPromise
+  async getDBs(options: ListDatabasesOptions = {}): Promise<{ databases: {name: string, sizeOnDisk: number, empty: boolean}[] }> {
+    this._emitMongoApiCall('getDBs', { options });
+    return await this._listDatabases(options);
+  }
+
+  @returnsPromise
+  async getDBNames(options: ListDatabasesOptions = {}): Promise<string[]> {
+    this._emitMongoApiCall('getDBNames', { options });
+    return (await this._listDatabases(options)).databases.map(db => db.name);
+  }
+
   @returnsPromise
   async show(cmd: string, arg?: string): Promise<CommandResult> {
     this._internalState.messageBus.emit('mongosh:show', { method: `show ${cmd}` });
 
     switch (cmd) {
       case 'databases':
       case 'dbs':
-        const result = await this._listDatabases({ readPreference: 'primaryPreferred' });
+        const result = (await this._listDatabases({ readPreference: 'primaryPreferred' })).databases;
         return new CommandResult('ShowDatabasesResult', result);
       case 'collections':
       case 'tables':