Merge pull request #24 from Mohamedhazeem/master

resolves #17, #23

Author: harsh98trivedi

calc.js

@@ -10,15 +10,18 @@ document.getElementById("answer").readOnly = true; //set this attribute in Html
 let screen = document.getElementById("answer");
 buttons = document.querySelectorAll("button");
 let screenValue = "";
+let lastScreenValue = "";
 let maxItems = 6;
+let isSign = true;
 for (item of buttons) {
   item.addEventListener("click", (e) => {
     buttonText = e.target.innerText;
-    if (buttonText == "X") {
+    if (buttonText == "X" && !isSign) {
       if (flag == 1) {
         flag = 0;
       }
       buttonText = "*";
+      isSign = true;
       screenValue += buttonText;
       screen.value = screenValue;
     } else if (buttonText == "C") {
@@ -27,6 +30,7 @@ for (item of buttons) {
       }
       screenValue = "";
       screen.value = screenValue;
+      isSign = true;
     } else if (buttonText == "=") {
       checkForBracketMulti(); // automatically evaluates if no brackets
       //
@@ -38,42 +42,39 @@ for (item of buttons) {
         screenValue += buttonText;
       }
       screen.value = screenValue;
-      console.log("im an operator");
+      isSign = false;
     } else {
       if (flag == 1) {
         flag = 0;
       }
-      screenValue = screen.value + buttonText;
-      screen.value = screenValue;
+      if (!isSign){
+        screenValue = screen.value + buttonText;
+        screen.value = screenValue;
+        isSign = true;
+      }
     }
   });
 }
 
 document.addEventListener("keydown", function (event) {
-  if (event.shiftKey == 57) {
-    event.key = "(";
-  } else if (event.shiftKey == 48) {
-    event.key = ")";
-  } else if (event.shiftKey == 53) {
-    event.key = "%";
-  }
-  if (event.keyCode == 88) {
-    screenValue += "*";
-    screen.value = screenValue;
-  }
   if (
-    event.key <= 9 ||
-    event.key == "+" ||
-    event.key == "-" ||
-    event.key == "*" ||
-    event.key == "." ||
-    event.key == "/" ||
-    event.key == "%" ||
-    event.key == "(" ||
-    event.key == ")"
+    event.key <= 9
   ) {
     screenValue += event.key;
     screen.value = screenValue;
+    isSign = false;
+  }
+  if(!isSign && (event.key == "+" ||
+  event.key == "-" ||
+  event.key == "*" ||
+  event.key == "." ||
+  event.key == "/" ||
+  event.key == "%" ||
+  event.key == "(" ||
+  event.key == ")")){
+    screenValue += event.key;
+    screen.value = screenValue;
+    isSign = true;
   }
   if (event.key == "Enter" || event.key == "=") {
     event.preventDefault();
@@ -120,20 +121,26 @@ function addStr(str, index, stringToAdd) {
 
 function checkForBracketMulti() {
   // Check if there's a number directly infront of a bracket
+  isSign = false;
   if (
     screen.value.includes("(") &&
     !isNaN(screen.value.charAt(screen.value.indexOf("(") - 1))
   ) {
     window.onBracketMultiplication();
     return;
   } else {
-    screen.value = eval(screenValue);
-    let calcHistory = JSON.parse(localStorage.getItem("calcHistory")) || [];
-    if (calcHistory.length >= maxItems) {
-      calcHistory.shift();
+    if(eval(screenValue) !== undefined) 
+    {
+      screen.value = eval(screenValue);
+      lastScreenValue = screenValue;
+      screenValue = screen.value;
+      let calcHistory = JSON.parse(localStorage.getItem("calcHistory")) || [];
+      if (calcHistory.length >= maxItems) {
+        calcHistory.shift();
+      }
+      calcHistory.push({ lastScreenValue, result: screen.value });
+      localStorage.setItem("calcHistory", JSON.stringify(calcHistory));
     }
-    calcHistory.push({ screenValue, result: screen.value });
-    localStorage.setItem("calcHistory", JSON.stringify(calcHistory));
   }
   flag = 1;
 }

hist.js

@@ -22,7 +22,7 @@ function showHistory() {
             const element = calcHistory[index];
             let historyItem = document.createElement('div');
             historyItem.className = 'historyelement';
-            historyItem.innerHTML = `${element.screenValue} =  ${element.result}`;
+            historyItem.innerHTML = `${element.lastScreenValue} =  ${element.result}`;
             history.appendChild(historyItem);
             if (index > 0) history.appendChild(document.createElement('hr'));
         }