filter NEES experiments to ensure we only show valid DOIs

designsafe/static/scripts/data-depot/components/modals/nees-doi-list.component.js

@@ -6,7 +6,7 @@ class NeesDoiListCtrl {
 
     $onInit() {
         this.project = this.resolve.project;
-        this.experimentDois = this.project.metadata.experiments.map((exp)=> {
+        this.experimentDois = this.project.metadata.experiments.filter(exp => !!exp.doi).map((exp)=> {
             const authors = (exp.creators ? exp.creators.map((author) => `${author.lastName}, ${author.firstName}`).join('; ') : '')
             const year = exp.endDate.split('T')[0].split('-')[0];
             const doi = exp.doi;