diff --git a/javascripts/src/lib/EventStack.spec.ts b/javascripts/src/lib/EventStack.spec.ts
new file mode 100644
index 000000000..8d780b9cc
--- /dev/null
+++ b/javascripts/src/lib/EventStack.spec.ts
@@ -0,0 +1,41 @@
+// License: LGPL-3.0-or-later
+import EventStack from './EventStack';
+
+describe('EventStack', () => {
+  const firstEvent = {type:"first"}
+  describe('.top', () => {
+    it('returns undefined if no events have been added', () => {
+      const stack = new EventStack();
+      expect(stack.top).toBeUndefined();
+    })
+
+    it('returns the top event after an event is pushed', () => {
+      const stack = new EventStack();
+      stack.push(firstEvent)
+      expect(stack.top).toEqual(firstEvent);
+    })
+  })
+
+  describe('.push', () => {
+    it("returns event when an event is added", () => {
+      const stack = new EventStack();
+      expect(stack.push(firstEvent)).toEqual(firstEvent)
+      
+    });
+
+    it ("returns undefined when the event isn't added because it's already the top", () => {
+      const stack = new EventStack();
+      stack.push(firstEvent)
+      expect(stack.push(firstEvent)).toBeUndefined();
+    })
+
+    it("returns and adds event when it doesn't match another object based on deep comparison", () => {
+      const stack = new EventStack();
+      stack.push(firstEvent)
+
+      const secondEvent = {type:"first", but:"different"}
+      expect(stack.push(secondEvent)).toEqual(secondEvent);
+    })
+  })
+
+})
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diff --git a/javascripts/src/lib/EventStack.ts b/javascripts/src/lib/EventStack.ts
new file mode 100644
index 000000000..8b5d0b0ac
--- /dev/null
+++ b/javascripts/src/lib/EventStack.ts
@@ -0,0 +1,34 @@
+// License: LGPL-3.0-or-later
+import last from 'lodash/last';
+import isEqual from 'lodash/isEqual'
+
+
+interface EventObjectBase {
+  type: string
+}
+
+/**
+ * A simple class for recording the list of events that occurred for a system
+ */
+export default class EventStack<TEventObjects extends EventObjectBase> {
+
+  private events:Array<TEventObjects> = []
+
+  push(event: TEventObjects): TEventObjects | undefined {
+    if (!this.top) {
+      this.events.push(event)
+      return event;
+    }
+    else if (!isEqual(this.top, event)) {
+      this.events.push(event);
+      return event;
+    }
+    return undefined;
+  }
+
+  get top(): TEventObjects | undefined {
+    return last(this.events);
+  }
+
+
+}
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