it works!

app/components/folder.hbs

 <div class="node folder">
     <div class="icon folder"></div>
     <div class="title">
-        <LinkTo @route="node" @model={{@model}}>
+        <LinkTo @route="node" @model={{@model.id}}>
             {{@model.title}}
         </LinkTo>
     </div>

app/components/nodes.hbs

@@ -3,9 +3,7 @@ All Nodes
   <ul class="results">
       {{#each @nodes as |node|}}
         <li class="item">
-          title={{ @node.title }}
-          type={{@node.type}}
-          {{#if @node.is_document }}
+          {{#if node.is_document }}
             <Document @model={{node}} />
           {{ else }}
             <Folder @model={{node}} />

app/routes/index.js

@@ -8,11 +8,14 @@ export default class IndexRoute extends Route {
   async model() {
     let response = await fetch('/api/nodes.json');
     let { data } = await response.json();
+    let ret;
 
-    return data.map((model) => {
+    ret = data.map((model) => {
       let { id, type, attributes } = model;
 
       return this.store.createRecord('node',{ id, type, ...attributes });
     });
+
+    return ret;
   }
 }

app/routes/node.js

@@ -6,6 +6,9 @@ export default class FolderRoute extends Route {
   @service store;
 
   async model(params) {
-    return this.store.findRecord('node', params.node_id, {include: "children"});
+    return this.store.findRecord(
+      'node',
+      params.node_id, {include: "children"}
+    );
   }
 }