From c83f82d5a0d3d8c6165b63608f460881c5e6cee0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Bajto=C5=A1?= <mbajtoss@gmail.com>
Date: Tue, 21 Apr 2020 14:11:50 +0200
Subject: [PATCH] feat: implement DataSource.stop()
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Implement `stop` as an alias for `disconnect`. This way LB4 applications
don't have to include custom `stop` implementation in every datasource
file.

Signed-off-by: Miroslav Bajtoš <mbajtoss@gmail.com>
---
 lib/datasource.js       |  8 ++++++++
 test/datasource.test.js | 25 +++++++++++++++++++++++++
 types/datasource.d.ts   |  3 +++
 3 files changed, 36 insertions(+)

diff --git a/lib/datasource.js b/lib/datasource.js
index 64ec82ba..82b09cee 100644
--- a/lib/datasource.js
+++ b/lib/datasource.js
@@ -2220,6 +2220,14 @@ DataSource.prototype.disconnect = function disconnect(cb) {
   return cb.promise;
 };
 
+/**
+ * An alias for `disconnect` to make the datasource a LB4 life-cycle observer.
+ * Please note that we are intentionally not providing a `start` method,
+ * because the logic for establishing connection(s) is more complex
+ * and usually started immediately from the datasoure constructor.
+ */
+DataSource.prototype.stop = DataSource.prototype.disconnect;
+
 /**
  * Copy the model from Master.
  * @param {Function} Master The model constructor
diff --git a/test/datasource.test.js b/test/datasource.test.js
index 0d47b9bc..b3127d02 100644
--- a/test/datasource.test.js
+++ b/test/datasource.test.js
@@ -330,6 +330,31 @@ describe('DataSource', function() {
     });
   });
 
+  it('provides stop() API calling disconnect', function(done) {
+    const mockConnector = {
+      name: 'loopback-connector-mock',
+      initialize: function(ds, cb) {
+        ds.connector = mockConnector;
+        process.nextTick(function() {
+          cb(null);
+        });
+      },
+    };
+
+    const dataSource = new DataSource(mockConnector);
+    dataSource.on('connected', function() {
+      // DataSource is now connected
+      // connected: true, connecting: false
+      dataSource.connected.should.be.true();
+      dataSource.connecting.should.be.false();
+
+      dataSource.stop(() => {
+        dataSource.connected.should.be.false();
+        done();
+      });
+    });
+  });
+
   describe('deleteModelByName()', () => {
     it('removes the model from ModelBuilder registry', () => {
       const ds = new DataSource('ds', {connector: 'memory'});
diff --git a/types/datasource.d.ts b/types/datasource.d.ts
index 3053baf2..34228b7a 100644
--- a/types/datasource.d.ts
+++ b/types/datasource.d.ts
@@ -287,6 +287,9 @@ export declare class DataSource extends EventEmitter {
   // legacy callback style
   disconnect(callback: Callback): void;
 
+  // Only promise variant, callback is intentionally not described.
+  stop(): Promise<void>;
+
   ping(): Promise<void>;
   // legacy callback style
   ping(callback: Callback): void;