FEATURE: adds plugin sharing api

app/assets/javascripts/discourse/lib/plugin-api.js.es6

@@ -26,9 +26,10 @@ import { addGTMPageChangedCallback } from 'discourse/lib/page-tracker';
 import { registerCustomAvatarHelper } from 'discourse/helpers/user-avatar';
 import { disableNameSuppression } from 'discourse/widgets/poster-name';
 import { registerCustomPostMessageCallback as registerCustomPostMessageCallback1 } from 'discourse/controllers/topic';
+import Sharing from 'discourse/lib/sharing';
 
 // If you add any methods to the API ensure you bump up this number
-const PLUGIN_API_VERSION = '0.8.22';
+const PLUGIN_API_VERSION = '0.8.23';
 
 class PluginApi {
   constructor(version, container) {
@@ -710,6 +711,21 @@ class PluginApi {
   addGTMPageChangedCallback(fn) {
     addGTMPageChangedCallback(fn);
   }
+
+  /**
+  *
+  * Registers a function that can add a new sharing source
+  *
+  * Example:
+  *
+  * // read /discourse/lib/sharing.js.es6 for options
+  * addSharingSource(options)
+  *
+  */
+  addSharingSource(options) {
+    Sharing.addSharingId(options.id);
+    Sharing.addSource(options);
+  }
 }
 
 let _pluginv01;

app/assets/javascripts/discourse/lib/sharing.js.es6

@@ -26,20 +26,37 @@
   ```
 **/
 
-var _sources = {};
+let _sources = {};
+let _customSharingIds = [];
 
 export default {
+  // allows to by pass site settings and add a sharing id through plugin api
+  // useful for theme components for example when only few users want to add
+  // sharing to a specific third party
+  addSharingId(id) {
+    _customSharingIds.push(id);
+  },
+
   addSource(source) {
     // backwards compatibility for plugins
     if (source.faIcon) {
-      source.icon = source.faIcon.replace('fa-', '');
+      source.icon = source.faIcon.replace("fa-", "");
       delete source.faIcon;
     }
 
     _sources[source.id] = source;
   },
 
-  activeSources(linksSetting) {
-    return linksSetting.split('|').map(s => _sources[s]).compact();
+  activeSources(linksSetting = "") {
+    return linksSetting
+      .split("|")
+      .concat(_customSharingIds)
+      .map(s => _sources[s])
+      .compact();
+  },
+
+  _reset() {
+    _sources = {};
+    _customSharingIds = [];
   }
 };

test/javascripts/lib/sharing-test.js.es6

@@ -0,0 +1,42 @@
+import Sharing from "discourse/lib/sharing";
+
+QUnit.module("lib:sharing", {
+  beforeEach() {
+    Sharing._reset();
+  }
+});
+
+QUnit.test("addSource", assert => {
+  const sharingSettings = "facebook|twitter";
+
+  assert.blank(Sharing.activeSources(sharingSettings));
+
+  Sharing.addSource({
+    id: "facebook"
+  });
+
+  assert.equal(Sharing.activeSources(sharingSettings).length, 1);
+});
+
+QUnit.test("addSharingId", assert => {
+  const sharingSettings = "";
+
+  assert.blank(Sharing.activeSources(sharingSettings));
+
+  Sharing.addSource({
+    id: "new-source"
+  });
+
+  assert.blank(
+    Sharing.activeSources(sharingSettings),
+    "it doesn’t activate a source not in settings"
+  );
+
+  Sharing.addSharingId("new-source");
+
+  assert.equal(
+    Sharing.activeSources(sharingSettings).length,
+    1,
+    "it adds sharing id to existing sharing settings"
+  );
+});