diff --git a/scm-ui/ui-components/src/repos/DiffFile.tsx b/scm-ui/ui-components/src/repos/DiffFile.tsx
index fe35cc111f..942d789f99 100644
--- a/scm-ui/ui-components/src/repos/DiffFile.tsx
+++ b/scm-ui/ui-components/src/repos/DiffFile.tsx
@@ -222,6 +222,14 @@ class DiffFile extends React.Component<Props, State> {
     return <ChangeTypeTag className={classNames("is-rounded", "has-text-weight-normal")} color={color} label={value} />;
   };
 
+  concat = (array: object[][]) => {
+    if (array.length > 0) {
+      return array.reduce((a, b) => a.concat(b));
+    } else {
+      return [];
+    }
+  };
+
   render() {
     const { file, fileControlFactory, fileAnnotationFactory, t } = this.props;
     const { collapsed, sideBySide } = this.state;
@@ -236,7 +244,7 @@ class DiffFile extends React.Component<Props, State> {
         <div className="panel-block is-paddingless">
           {fileAnnotations}
           <ModifiedDiffComponent className={viewType} viewType={viewType} hunks={file.hunks} diffType={file.type}>
-            {(hunks: HunkType[]) => hunks.map(this.renderHunk).reduce((a, b) => a.concat(b))}
+            {(hunks: HunkType[]) => this.concat(hunks.map(this.renderHunk))}
           </ModifiedDiffComponent>
         </div>
       );