fix: don't assign example if an example does not exist (#4365)

fixes #4319

src/core/plugins/samples/fn.js

@@ -73,13 +73,13 @@ export const sampleFromSchema = (schema, config={}) => {
   }
 
   if(type === "array") {
-    if(Array.isArray(items.anyOf)) { 
-      return items.anyOf.map(i => sampleFromSchema(i, config)) 
-    } 
-  
-    if(Array.isArray(items.oneOf)) { 
-      return items.oneOf.map(i => sampleFromSchema(i, config)) 
-    } 
+    if(Array.isArray(items.anyOf)) {
+      return items.anyOf.map(i => sampleFromSchema(i, config))
+    }
+
+    if(Array.isArray(items.oneOf)) {
+      return items.oneOf.map(i => sampleFromSchema(i, config))
+    }
 
     return [ sampleFromSchema(items, config) ]
   }
@@ -214,7 +214,9 @@ export const sampleXmlFromSchema = (schema, config={}) => {
           || enumAttrVal || primitive(props[propName])
       } else {
         props[propName].xml.name = props[propName].xml.name || propName
-        props[propName].example = props[propName].example !== undefined ? props[propName].example : example[propName]
+        if(props[propName].example === undefined && example[propName] !== undefined) {
+          props[propName].example = example[propName]
+        }
         let t = sampleXmlFromSchema(props[propName])
         if (Array.isArray(t)) {
           res[displayName] = res[displayName].concat(t)