simple-calculator/script.js at master · TySod/simple-calculator · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
// Simple Calculator Script

let display = document.querySelector(".display").value;
let justCalculated = false;
function updateDisplay() {
    document.querySelector(".display").value = display;
}

function appendChar(char) {
     if (justCalculated) {
        display = "";
        justCalculated = false;
    }
    display += char;
    updateDisplay();
}

function clearScreen() {
    display = "";
    updateDisplay();
}

function deleteChar() {
    display = display.slice(0, -1);
    updateDisplay();
}
function percent() {
    try {
        display = (eval(display) / 100).toString();
    } catch {
        display = "Error";
    }
    updateDisplay();
}

function appendDot() {
     if (justCalculated) {
        display = "";
        justCalculated = false;
    }
    // Prevent multiple dots in the current number
    const parts = display.split(/[\+\-\*\/]/);
    const lastPart = parts[parts.length - 1];
    if (!lastPart.includes('.')) {
        display += '.';
        updateDisplay();
    }
}
function calculate() {
   try {
        display = eval(display).toString();
    } catch {
        display = "Error";
    }
    updateDisplay();
    justCalculated = true;
}


document.addEventListener('keydown', function(event) {
    const key = event.key;
    if (!isNaN(key)) {
        appendChar(key);
    } else if (['+', '-', '*', '/'].includes(key)) {
        appendChar(key);
    } else if (key === 'Enter' || key === '=') {
        event.preventDefault();
        calculate();
    } else if (key === 'Backspace') {
        deleteChar();
    } else if (key === 'Escape') {
        clearScreen();
    } else if (key === '.') {
        appendDot();
    } else if (key === '%') {
        percent();
    }
});