Embed metrics undefined param fix

app/assets/javascripts/monitoring/components/dashboard.vue

@@ -264,12 +264,12 @@ export default {
     showToast() {
       this.$toast.show(__('Link copied to clipboard'));
     },
+    // TODO: END
     generateLink(group, title, yLabel) {
       const dashboard = this.currentDashboard || this.firstDashboard.path;
-      const params = { dashboard, group, title, y_label: yLabel };
+      const params = _.pick({ dashboard, group, title, y_label: yLabel }, value => value != null);
       return mergeUrlParams(params, window.location.href);
     },
-    // TODO: END
     hideAddMetricModal() {
       this.$refs.addMetricModal.hide();
     },

changelogs/unreleased/tr-param-undefined-fix.yml

+---
+title: Fix for embedded metrics undefined params
+merge_request: 31975
+author:
+type: fixed

spec/javascripts/monitoring/dashboard_spec.js

@@ -414,6 +414,26 @@ describe('Dashboard', () => {
       expect(clipboardText()).toContain(`y_label=`);
     });
 
+    it('undefined parameter is stripped', done => {
+      wrapper.setProps({ currentDashboard: undefined });
+
+      wrapper.vm.$nextTick(() => {
+        expect(clipboardText()).not.toContain(`dashboard=`);
+        expect(clipboardText()).toContain(`y_label=`);
+        done();
+      });
+    });
+
+    it('null parameter is stripped', done => {
+      wrapper.setProps({ currentDashboard: null });
+
+      wrapper.vm.$nextTick(() => {
+        expect(clipboardText()).not.toContain(`dashboard=`);
+        expect(clipboardText()).toContain(`y_label=`);
+        done();
+      });
+    });
+
     it('creates a toast when clicked', () => {
       spyOn(wrapper.vm.$toast, 'show').and.stub();