diff --git a/ui/app/adapters/application.js b/ui/app/adapters/application.js
index 3373fef90..5a4d99804 100644
--- a/ui/app/adapters/application.js
+++ b/ui/app/adapters/application.js
@@ -28,7 +28,7 @@ export default class Application extends RESTAdapter {
       };
     }
 
-    return;
+    return undefined;
   }
 
   handleResponse(status, headers, payload) {
diff --git a/ui/app/components/allocation-row.js b/ui/app/components/allocation-row.js
index c5d829b26..0a9fb1c0a 100644
--- a/ui/app/components/allocation-row.js
+++ b/ui/app/components/allocation-row.js
@@ -30,7 +30,7 @@ export default class AllocationRow extends Component {
 
   @computed('allocation', 'allocation.isRunning')
   get stats() {
-    if (!this.get('allocation.isRunning')) return;
+    if (!this.get('allocation.isRunning')) return undefined;
 
     return AllocationStatsTracker.create({
       fetch: url => this.token.authorizedRequest(url),
diff --git a/ui/app/components/allocation-stat.js b/ui/app/components/allocation-stat.js
index b740910e0..814d43e52 100644
--- a/ui/app/components/allocation-stat.js
+++ b/ui/app/components/allocation-stat.js
@@ -29,12 +29,12 @@ export default class AllocationStat extends Component {
       return this[this.metric];
     }
 
-    return;
+    return undefined;
   }
 
   @computed('metric', 'stat.used')
   get formattedStat() {
-    if (!this.stat) return;
+    if (!this.stat) return undefined;
     if (this.metric === 'memory') return formatBytes([this.stat.used]);
     return this.stat.used;
   }
@@ -43,6 +43,6 @@ export default class AllocationStat extends Component {
   get formattedReserved() {
     if (this.metric === 'memory') return `${this.statsTracker.reservedMemory} MiB`;
     if (this.metric === 'cpu') return `${this.statsTracker.reservedCPU} MHz`;
-    return;
+    return undefined;
   }
 }
diff --git a/ui/app/components/fs/browser.js b/ui/app/components/fs/browser.js
index d18a15777..7dbfd7183 100644
--- a/ui/app/components/fs/browser.js
+++ b/ui/app/components/fs/browser.js
@@ -24,7 +24,7 @@ export default class Browser extends Component {
       return this.model;
     }
 
-    return;
+    return undefined;
   }
 
   @computed('taskState')
diff --git a/ui/app/components/fs/file.js b/ui/app/components/fs/file.js
index 4b282bb1c..e977c7519 100644
--- a/ui/app/components/fs/file.js
+++ b/ui/app/components/fs/file.js
@@ -69,7 +69,7 @@ export default class File extends Component {
       return 'readat';
     }
 
-    return;
+    return undefined;
   }
 
   @computed('allocation.{id,node.httpAddr}', 'fetchMode', 'useServer')
diff --git a/ui/app/components/image-file.js b/ui/app/components/image-file.js
index 2e359a171..16ee6733c 100644
--- a/ui/app/components/image-file.js
+++ b/ui/app/components/image-file.js
@@ -19,7 +19,7 @@ export default class ImageFile extends Component {
 
   @computed('src')
   get fileName() {
-    if (!this.src) return;
+    if (!this.src) return undefined;
     return this.src.includes('/') ? this.src.match(/^.*\/(.*)$/)[1] : this.src;
   }
 
diff --git a/ui/app/components/lifecycle-chart-row.js b/ui/app/components/lifecycle-chart-row.js
index f63a50eba..44985d747 100644
--- a/ui/app/components/lifecycle-chart-row.js
+++ b/ui/app/components/lifecycle-chart-row.js
@@ -12,7 +12,7 @@ export default class LifecycleChartRow extends Component {
       return 'is-active';
     }
 
-    return;
+    return undefined;
   }
 
   @computed('taskState.finishedAt')
@@ -21,6 +21,6 @@ export default class LifecycleChartRow extends Component {
       return 'is-finished';
     }
 
-    return;
+    return undefined;
   }
 }
diff --git a/ui/app/components/task-row.js b/ui/app/components/task-row.js
index feeb36ef1..28094acd1 100644
--- a/ui/app/components/task-row.js
+++ b/ui/app/components/task-row.js
@@ -29,14 +29,14 @@ export default class TaskRow extends Component {
   // Since all tasks for an allocation share the same tracker, use the registry
   @computed('task', 'task.isRunning')
   get stats() {
-    if (!this.get('task.isRunning')) return;
+    if (!this.get('task.isRunning')) return undefined;
 
     return this.statsTrackersRegistry.getTracker(this.get('task.allocation'));
   }
 
   @computed('task.name', 'stats.tasks.[]')
   get taskStats() {
-    if (!this.stats) return;
+    if (!this.stats) return undefined;
 
     return this.get('stats.tasks').findBy('task', this.get('task.name'));
   }
diff --git a/ui/app/models/job.js b/ui/app/models/job.js
index 9d5b495e6..e179cd4b4 100644
--- a/ui/app/models/job.js
+++ b/ui/app/models/job.js
@@ -174,7 +174,7 @@ export default class Job extends Model {
       return failureEvaluations.sortBy('modifyIndex').get('lastObject');
     }
 
-    return;
+    return undefined;
   }
 
   @equal('type', 'service') supportsDeployments;
@@ -185,7 +185,7 @@ export default class Job extends Model {
   get runningDeployment() {
     const latest = this.latestDeployment;
     if (latest.get('isRunning')) return latest;
-    return;
+    return undefined;
   }
 
   fetchRawDefinition() {
diff --git a/ui/app/models/node-attributes.js b/ui/app/models/node-attributes.js
index 2f24d9bb9..810fab2c6 100644
--- a/ui/app/models/node-attributes.js
+++ b/ui/app/models/node-attributes.js
@@ -13,7 +13,7 @@ export default class NodeAttributes extends Fragment {
     const original = this.nodeAttributes;
 
     if (!original) {
-      return;
+      return undefined;
     }
 
     // `unflatten` doesn't sort keys before unflattening, so manual preprocessing is necessary.
diff --git a/ui/app/models/node.js b/ui/app/models/node.js
index d56d28ca6..2e69d56aa 100644
--- a/ui/app/models/node.js
+++ b/ui/app/models/node.js
@@ -74,7 +74,7 @@ export default class Node extends Model {
       return allocation.modifyTime;
     }
 
-    return;
+    return undefined;
   }
 
   @fragmentArray('node-driver') drivers;
diff --git a/ui/app/services/token.js b/ui/app/services/token.js
index d829431d9..78d43feb1 100644
--- a/ui/app/services/token.js
+++ b/ui/app/services/token.js
@@ -47,7 +47,7 @@ export default class TokenService extends Service {
   @computed('secret', 'fetchSelfToken.lastSuccessful.value')
   get selfToken() {
     if (this.secret) return this.get('fetchSelfToken.lastSuccessful.value');
-    return;
+    return undefined;
   }
 
   @task(function*() {