From 514596f964547ec1a2f5e7548937a2d85f0b3848 Mon Sep 17 00:00:00 2001
From: Oliver Schwendener <oliver.schwendener@hotmail.com>
Date: Fri, 8 Feb 2019 18:36:59 +0100
Subject: [PATCH] Calculator: treat user input as invalid If math.eval returns
 undefined (Fixes #108)

---
 .../unit/input-validators/calculator-input-validator.test.ts  | 2 ++
 src/ts/calculator/calculator.ts                               | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/src/tests/unit/input-validators/calculator-input-validator.test.ts b/src/tests/unit/input-validators/calculator-input-validator.test.ts
index 87cdf1135..3ee4ea5c3 100644
--- a/src/tests/unit/input-validators/calculator-input-validator.test.ts
+++ b/src/tests/unit/input-validators/calculator-input-validator.test.ts
@@ -24,6 +24,8 @@ describe(CalculatorInputValidator.name, (): void => {
 
         it("should return false when passing in an invalid argument", (): void => {
             const invalidInputs = [
+                "#",
+                "#2",
                 "s",
                 "kg",
                 "log()",
diff --git a/src/ts/calculator/calculator.ts b/src/ts/calculator/calculator.ts
index 81890ac19..266e74f1b 100644
--- a/src/ts/calculator/calculator.ts
+++ b/src/ts/calculator/calculator.ts
@@ -18,6 +18,10 @@ export class Calculator {
         } catch (e) {
             return false;
         }
+
+        if (result === undefined) {
+            return false;
+        }
         return !isNaN(result) || this.isValidMathType(result) || false;
     }