Expose MultiDB within Firestore (#2209)

* Expose MultiDB within Firestore

* Expose MultiDB within Firestore

Author: tom-andersen

etc/firebase-admin.firestore.api.md

@@ -100,11 +100,20 @@ export function getFirestore(): Firestore;
 // @public
 export function getFirestore(app: App): Firestore;
 
+// @beta
+export function getFirestore(databaseId: string): Firestore;
+
+// @beta
+export function getFirestore(app: App, databaseId: string): Firestore;
+
 export { GrpcStatus }
 
 // @public
 export function initializeFirestore(app: App, settings?: FirestoreSettings): Firestore;
 
+// @beta
+export function initializeFirestore(app: App, settings: FirestoreSettings, databaseId: string): Firestore;
+
 export { NestedUpdateFields }
 
 export { OrderByDirection }

src/firestore/index.ts

@@ -75,58 +75,72 @@ export {
 export { FirestoreSettings };
 
 /**
- * Gets the {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * Gets the default {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
  * service for the default app.
  *
- * `getFirestore()` can be called with no arguments to access the default
- * app's `Firestore` service or as `getFirestore(app)` to access the
- * `Firestore` service associated with a specific app.
- *
  * @example
  * ```javascript
- * // Get the Firestore service for the default app
+ * // Get the default Firestore service for the default app
  * const defaultFirestore = getFirestore();
  * ```
 
  * @returns The default {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
- *   service if no app is provided or the `Firestore` service associated with the
- *   provided app.
+ * service for the default app.
  */
 export function getFirestore(): Firestore;
 
 /**
- * Gets the {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * Gets the default {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
  * service for the given app.
  *
- * `getFirestore()` can be called with no arguments to access the default
- * app's `Firestore` service or as `getFirestore(app)` to access the
- * `Firestore` service associated with a specific app.
- *
  * @example
  * ```javascript
- * // Get the Firestore service for a specific app
+ * // Get the default Firestore service for a specific app
  * const otherFirestore = getFirestore(app);
  * ```
  *
- * @param App - which `Firestore` service to
- *   return. If not provided, the default `Firestore` service will be returned.
+ * @param app - which `Firestore` service to return.
  *
  * @returns The default {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
- *   service if no app is provided or the `Firestore` service associated with the
- *   provided app.
+ * service associated with the provided app.
  */
 export function getFirestore(app: App): Firestore;
 
 /**
- * @param databaseId
- * @internal
+ * Gets the named {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * service for the default app.
+ *
+ * @example
+ * ```javascript
+ * // Get the Firestore service for a named database and default app
+ * const otherFirestore = getFirestore('otherDb');
+ * ```
+ *
+ * @param databaseId - name of database to return.
+ *
+ * @returns The named {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * service for the default app.
+ * @beta
  */
 export function getFirestore(databaseId: string): Firestore;
 
 /**
- * @param app
- * @param databaseId
- * @internal
+ * Gets the named {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * service for the given app.
+ *
+ * @example
+ * ```javascript
+ * // Get the Firestore service for a named database and specific app.
+ * const otherFirestore = getFirestore('otherDb');
+ * ```
+ *
+ * @param app - which `Firestore` service to return.
+ *
+ * @param databaseId - name of database to return.
+ *
+ * @returns The named {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * service associated with the provided app.
+ * @beta
  */
 export function getFirestore(app: App, databaseId: string): Firestore;
 
@@ -144,7 +158,7 @@ export function getFirestore(
 }
 
 /**
- * Gets the {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * Gets the default {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
  * service for the given app, passing extra parameters to its constructor.
  *
  * @example
@@ -153,20 +167,32 @@ export function getFirestore(
  * const otherFirestore = initializeFirestore(app, {preferRest: true});
  * ```
  *
- * @param App - which `Firestore` service to
- *   return. If not provided, the default `Firestore` service will be returned.
- * 
+ * @param app - which `Firestore` service to return.
+ *
  * @param settings - Settings object to be passed to the constructor.
  *
- * @returns The `Firestore` service associated with the provided app and settings.
+ * @returns The default `Firestore` service associated with the provided app and settings.
  */
 export function initializeFirestore(app: App, settings?: FirestoreSettings): Firestore;
 
 /**
- * @param app 
- * @param settings 
- * @param databaseId 
- * @internal
+ * Gets the named {@link https://googleapis.dev/nodejs/firestore/latest/Firestore.html | Firestore}
+ * service for the given app, passing extra parameters to its constructor.
+ *
+ * @example
+ * ```javascript
+ * // Get the Firestore service for a specific app, require HTTP/1.1 REST transport
+ * const otherFirestore = initializeFirestore(app, {preferRest: true}, 'otherDb');
+ * ```
+ *
+ * @param app - which `Firestore` service to return.
+ *
+ * @param settings - Settings object to be passed to the constructor.
+ *
+ * @param databaseId - name of database to return.
+ *
+ * @returns The named `Firestore` service associated with the provided app and settings.
+ * @beta
  */
 export function initializeFirestore(
   app: App,