Fixed bug Lack of Input Validation and Error Handling in Calculator thinkswell#1164 for one project

Author: lyepez-glitch

Calculator/Pratik1968/main.js

@@ -3,60 +3,90 @@ let value = ""
 let ans = 0
 
 
-function setInput(){
-    let input  = document.getElementById("ans");
+function setInput() {
+    let input = document.getElementById("ans");
     input.value = value
 }
 
-window.onload = function () {
+window.onload = function() {
     setInput()
 }
-function NumberButtonClick(number){
 
-value +=number
+function NumberButtonClick(number) {
+    let lastChar = value[value.length - 1];
 
-setInput()
+    if (lastChar === '/' && number === 0) {
+        alert("Error: Division by zero is undefined.");
+        return null;
+    } else {
+        value += number
+    }
+
+
+    setInput()
 }
-function functionButton(Function){
-  
-    let input  = document.getElementById("ans");
-    if (input.value =="" || input.value==null) {return ;}
-   switch(Function){
-case functionVar.add:
-  
-value+="+";
-break;
-case functionVar.substraction:
-    value+="-";
-break;
-case functionVar.multiplication:
-    value+="x";
-break;
-case functionVar.equal:
-ans = eval(value.replace("x","*").replace("%","*1/100").replace("^","**"));
-value = ans;
-break;
-case functionVar.division:
-    value+="/";
-break;
-case functionVar.percentage:
-    value+="%";
-break;
-case functionVar.power:
-value += "^";
-break;
-case functionVar.clear:
-    value = "";
-    break;
-case functionVar.backspace:
-value  =value.slice(0,-1)    
-break;
-case functionVar.decimal:
-    value+=".";
-break;
+
+function isOperator(value) {
+    const operators = ['+', '-', '.', '^', '%', '/', 'x'];
+    if (operators.includes(value)) {
+        return true;
+    }
+    return false;
 }
 
+function functionButton(Function) {
+
+    let input = document.getElementById("ans");
+    if (input.value == "" || input.value == null) { return; }
+    let lastChar = value[value.length - 1];
 
-setInput()
+    if (isOperator(lastChar) && Function !== '8') {
+        return;
+    }
+
+
+    switch (Function) {
+        case functionVar.add:
+            if (lastChar !== "+")
+                value += "+";
+            break;
+        case functionVar.substraction:
+            if (lastChar !== "-")
+                value += "-";
+            break;
+        case functionVar.multiplication:
+            if (lastChar !== "x")
+                value += "x";
+            break;
+        case functionVar.equal:
+            ans = eval(value.replace("x", "*").replace("%", "*1/100").replace("^", "**"));
+            value = ans;
+            break;
+        case functionVar.division:
+            if (lastChar !== "/")
+                value += "/";
+            break;
+        case functionVar.percentage:
+            if (lastChar !== "%")
+                value += "%";
+            break;
+        case functionVar.power:
+            if (lastChar !== "^")
+                value += "^";
+            break;
+        case functionVar.clear:
+            value = "";
+            break;
+        case functionVar.backspace:
+            value = value.slice(0, -1)
+            break;
+        case functionVar.decimal:
+            if (lastChar !== "." && !value.includes('.'))
+                value += ".";
+            break;
+    }
+
+
+    setInput()
 
 }