Feature: Workspaces, at All Boards page.

Thanks to xet7 !

client/lib/boardMultiSelection.js

@@ -0,0 +1,73 @@
+import { ReactiveCache } from '/imports/reactiveCache';
+
+BoardMultiSelection = {
+  _selectedBoards: new ReactiveVar([]),
+
+  _isActive: new ReactiveVar(false),
+
+  reset() {
+    this._selectedBoards.set([]);
+  },
+
+  isActive() {
+    return this._isActive.get();
+  },
+
+  count() {
+    return this._selectedBoards.get().length;
+  },
+
+  isEmpty() {
+    return this.count() === 0;
+  },
+
+  getSelectedBoardIds() {
+    return this._selectedBoards.get();
+  },
+
+  activate() {
+    if (!this.isActive()) {
+      this._isActive.set(true);
+      Tracker.flush();
+    }
+  },
+
+  disable() {
+    if (this.isActive()) {
+      this._isActive.set(false);
+      this.reset();
+    }
+  },
+
+  add(boardIds) {
+    return this.toggle(boardIds, { add: true, remove: false });
+  },
+
+  remove(boardIds) {
+    return this.toggle(boardIds, { add: false, remove: true });
+  },
+
+  toogle(boardIds) {
+    return this.toggle(boardIds, { add: true, remove: true });
+  },
+
+  toggle(boardIds, { add, remove } = {}) {
+    boardIds = _.isString(boardIds) ? [boardIds] : boardIds;
+    let selectedBoards = this._selectedBoards.get();
+
+    boardIds.forEach(boardId => {
+      const index = selectedBoards.indexOf(boardId);
+      if (index > -1 && remove) {
+        selectedBoards = selectedBoards.filter(id => id !== boardId);
+      } else if (index === -1 && add) {
+        selectedBoards.push(boardId);
+      }
+    });
+
+    this._selectedBoards.set(selectedBoards);
+  },
+
+  isSelected(boardId) {
+    return this._selectedBoards.get().includes(boardId);
+  },
+};