diff --git a/src/components/FunctionDefinition.js b/src/components/FunctionDefinition.js
index fd56361ac..395b866e2 100644
--- a/src/components/FunctionDefinition.js
+++ b/src/components/FunctionDefinition.js
@@ -4,10 +4,14 @@ import CodeDef from './CodeDef';
 import { graphql } from 'gatsby';
 
 const FunctionDefinition = ({ className, arguments: params, returnValue }) => {
-  if (!params.length && !returnValue.length) {
+  if (!params.length && !returnValue && !returnValue.length) {
     return null;
   }
 
+  if (!Array.isArray(returnValue)) {
+    returnValue = [returnValue];
+  }
+
   return (
     <CodeDef className={className}>
       <CodeDef.Keyword>function</CodeDef.Keyword>{' '}
@@ -30,7 +34,7 @@ const FunctionDefinition = ({ className, arguments: params, returnValue }) => {
       {params.length > 0 && <CodeDef.Bracket>)</CodeDef.Bracket>}
       {returnValue.length > 0 && (
         <>
-          <CodeDef.Operator> => </CodeDef.Operator>
+          <CodeDef.Operator> =&gt; </CodeDef.Operator>
           <CodeDef.Type>{returnValue[0].type}</CodeDef.Type>
         </>
       )}
@@ -38,6 +42,11 @@ const FunctionDefinition = ({ className, arguments: params, returnValue }) => {
   );
 };
 
+const ReturnValueType = PropTypes.shape({
+  type: PropTypes.string,
+  description: PropTypes.string,
+});
+
 FunctionDefinition.propTypes = {
   className: PropTypes.string,
   arguments: PropTypes.arrayOf(
@@ -47,12 +56,10 @@ FunctionDefinition.propTypes = {
       description: PropTypes.string,
     })
   ).isRequired,
-  returnValue: PropTypes.arrayOf(
-    PropTypes.shape({
-      type: PropTypes.string,
-      description: PropTypes.string,
-    })
-  ).isRequired,
+  returnValue: PropTypes.oneOfType([
+    ReturnValueType,
+    PropTypes.arrayOf(ReturnValueType),
+  ]).isRequired,
 };
 
 export const query = graphql`