1 files changed, 5 insertions, 4 deletions
diff --git a/src/console/completion.js b/src/console/completion.js
index 0c21cb0..4c69afb 100644
--- a/src/console/completion.js
+++ b/src/console/completion.js
@@ -3,15 +3,16 @@ export default class Completion {
     if (typeof completions.length !== 'number') {
       throw new TypeError('completions does not have a length in number');
     }
-    this.completions = completions
+    this.completions = completions;
     this.index = 0;
   }
 
   prev() {
-    if (this.completions.length === 0) {
+    let length = this.completions.length;
+    if (length === 0) {
       return null;
     }
-    this.index = (this.index + this.completions.length - 1) % this.completions.length
+    this.index = (this.index + length - 1) % length;
     return this.completions[this.index];
   }
 
@@ -20,7 +21,7 @@ export default class Completion {
       return null;
     }
     let item = this.completions[this.index];
-    this.index = (this.index + 1) % this.completions.length
+    this.index = (this.index + 1) % this.completions.length;
     return item;
   }
 }