fix: don't crash but gracefully ignore undefined for wildcard keypaths

Author: webketje

src/expand-wildcard-keypath.js

@@ -48,6 +48,8 @@ function expandWildcardKeypath(root, keypaths, char) {
     if (wildcard > -1) {
       const pre = keypath.slice(0, wildcard)
       const wildcardRoot = get(root, pre)
+
+      if (!wildcardRoot) return result
       const looped = isArray(wildcardRoot) ? wildcardRoot : Object.keys(wildcardRoot)
 
       looped.forEach((entry, index) => {

src/index.js

@@ -112,7 +112,7 @@ function markdown(options = defaultOptions) {
           set(data, key, options.render(globalRefsMarkdown + value, options.engineOptions, { path: file, key }))
           // log a warning if the key is defined and of an unexpected type, but not if the property simply is not defined
         } else if (typeof value !== 'undefined') {
-          debug.warn('Couldn\'t render key %s of file "%s": not a string', key.join ? key.join('.') : key, file)
+          debug.warn('Couldn\'t render key "%s" of file "%s": not a string', key.join ? key.join('.') : key, file)
         }
       })