From 2ff9cfa6da1d6d30343acb2c4c678eedd39621ff Mon Sep 17 00:00:00 2001
From: "evelyn.graumann" <evelyn.graumann@crosslend.com>
Date: Thu, 23 Jan 2020 17:56:11 +0100
Subject: [PATCH] react tutorial: fix behaviour of 0 and .

---
 src/components/Calculator/Calculator.jsx     | 4 ++--
 src/components/Calculator/Calculator.spec.js | 7 ++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/components/Calculator/Calculator.jsx b/src/components/Calculator/Calculator.jsx
index 4ffd396..34dd120 100644
--- a/src/components/Calculator/Calculator.jsx
+++ b/src/components/Calculator/Calculator.jsx
@@ -87,9 +87,9 @@ class Calculator extends Component {
             // set displayValue to '0' if displayValue is empty string
             if (displayValue === '') displayValue = '0';
         } else {
-            // replace displayValue with value if displayValue equal to '0'
+            // replace displayValue with value if displayValue equal to '0' and it does not include the dot
             // else concatenate displayValue and value
-            displayValue === '0' ? displayValue = value : displayValue += value;
+            displayValue === '0' && value!== '.' ? displayValue = value : displayValue += value;
         }
 
         this.setState({ displayValue });
diff --git a/src/components/Calculator/Calculator.spec.js b/src/components/Calculator/Calculator.spec.js
index 9993680..a94ed06 100644
--- a/src/components/Calculator/Calculator.spec.js
+++ b/src/components/Calculator/Calculator.spec.js
@@ -88,6 +88,12 @@ describe('updateDisplay', () => {
         expect(wrapper.state('displayValue')).toEqual('0');
     });
 
+    it('prevents showing only . when 0 as initial value', () => {
+        wrapper.instance().updateDisplay('0');
+        wrapper.instance().updateDisplay('.');
+        expect(wrapper.state('displayValue')).toEqual('0.5');
+    });
+
     it('removes last char of displayValue', () => {
         wrapper.instance().updateDisplay('5');
         wrapper.instance().updateDisplay('0');
@@ -161,7 +167,6 @@ describe('callOperator', () => {
         expect(wrapper.state('displayValue')).toEqual('6.05');
     });
 
-
     it('updates displayValue to the sum of storedValue and displayValue', () => {
         wrapper.setState({ storedValue: '3' });
         wrapper.setState({ displayValue: '2' });