Allow functions to deploy to multiple regions (firebase#375)

* Reverts 3d2adbe, allows region() to accept multiple regions

* switch to loadash difference

* adds `

* changelog

Author: joehan

changelog.txt

@@ -1 +1,2 @@
+feature - support for multiple regions on functions by passing extra region strings to functions.regions()
 fixed - validation on instance name for realtime database triggers

spec/function-builder.spec.ts

@@ -42,17 +42,17 @@ describe('FunctionBuilder', () => {
     expect(fn.__trigger.regions).to.deep.equal(['us-east1']);
   });
 
-  // it('should allow multiple regions to be set', () => {
-  //   let fn = functions
-  //     .region('my-region', 'my-other-region')
-  //     .auth.user()
-  //     .onCreate(user => user);
-
-  //   expect(fn.__trigger.regions).to.deep.equal([
-  //     'my-region',
-  //     'my-other-region',
-  //   ]);
-  // });
+  it('should allow multiple regions to be set', () => {
+    let fn = functions
+      .region('us-east1', 'us-central1')
+      .auth.user()
+      .onCreate(user => user);
+
+    expect(fn.__trigger.regions).to.deep.equal([
+      'us-east1',
+      'us-central1',
+    ]);
+  });
 
   it('should allow runtime options to be set', () => {
     let fn = functions
@@ -135,6 +135,28 @@ describe('FunctionBuilder', () => {
         timeoutSeconds: 500,
       } as any);
     }).to.throw(Error);
+
+    expect(() => {
+      return functions.region('unsupported', 'us-east1');
+    }).to.throw(Error);
+
+    expect(() => {
+      return functions.region('unsupported', 'us-east1').runWith({
+        timeoutSeconds: 500,
+      } as any);
+    }).to.throw(Error);
+  });
+
+  it('should throw an error if user chooses no region when using .region()', () => {
+    expect(() => {
+      return functions.region();
+    }).to.throw(Error);
+
+    expect(() => {
+      return functions.region().runWith({
+        timeoutSeconds: 500,
+      } as any);
+    }).to.throw(Error);
   });
 
 });

src/function-builder.ts

@@ -36,23 +36,27 @@ import { CloudFunction, EventContext, Runnable, TriggerAnnotated } from './cloud
 
 /**
  * Configure the regions that the function is deployed to.
- * @param region Region string.
- * For example: `functions.region('us-east1')`
+ * @param regions One of more region strings.
+ * For example: `functions.region('us-east1')` or `functions.region('us-east1', 'us-central1')`
  */
-export function region(region: string) {
+export function region(...regions: string[]) {
+  if (!regions.length) {
+    throw new Error(
+      "You must specify at least one region"
+    );
+  }
   if (
-    !_.includes(
-      ['us-central1', 'us-east1', 'europe-west1', 'asia-northeast1'],
-      region
-    )
+    _.difference(
+      regions,
+      ['us-central1', 'us-east1', 'europe-west1', 'asia-northeast1']
+    ).length
   ) {
     throw new Error(
       "The only valid regions are 'us-central1', 'us-east1', 'europe-west1', and 'asia-northeast1'"
     );
   }
-  return new FunctionBuilder({ regions: [region] });
+  return new FunctionBuilder({ regions });
 }
-
 /**
  * Configure runtime options for the function.
  * @param runtimeOptions Object with 2 optional fields:
@@ -96,11 +100,11 @@ export class FunctionBuilder {
 
   /**
    * Configure the regions that the function is deployed to.
-   * @param region Region string.
-   * For example: `functions.region('us-east1')`
+   * @param regions One or more region strings.
+   * For example: `functions.region('us-east1')`  or `functions.region('us-east1', 'us-central1')`
    */
-  region = (region: string) => {
-    this.options.regions = [region];
+  region = (...regions: string[]) => {
+    this.options.regions = regions;
     return this;
   };