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153 lines (141 loc) · 5.19 KB
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const screen = document.getElementById('answer');
const buttons = document.querySelectorAll('.calc-btn');
const historyBtn = document.getElementById('history-btn');
const historyPanel = document.getElementById('history-panel');
const historyList = document.getElementById('history-list');
const closeHistory = document.getElementById('close-history');
const clearHistory = document.getElementById('clear-history');
const themeToggle = document.getElementById('theme-toggle');
// Theme toggle logic
function setTheme(mode) {
document.documentElement.classList.toggle('dark', mode === 'dark');
themeToggle.setAttribute('aria-pressed', mode === 'dark');
localStorage.setItem('theme', mode);
}
setTheme(localStorage.getItem('theme') || 'light');
themeToggle.onclick = () => {
const newMode = document.documentElement.classList.contains('dark') ? 'light' : 'dark';
setTheme(newMode);
};
// History logic
function getHistory() {
return JSON.parse(localStorage.getItem('calcHistory') || '[]');
}
function saveHistory(expr, res) {
let hist = getHistory();
hist.push({ expr, res });
if (hist.length > 50) hist.shift();
localStorage.setItem('calcHistory', JSON.stringify(hist));
}
function renderHistory() {
const hist = getHistory().slice().reverse();
historyList.innerHTML = hist.length
? hist.map(item => `<div class="flex justify-between p-3 rounded bg-gray-100 dark:bg-gray-700">
<span>${item.expr}</span>
<span class="${item.res < 0 ? 'text-red-500' : 'text-green-500'} font-bold">${item.res}</span>
</div>`).join('')
: `<p class="text-gray-500">No history yet</p>`;
}
historyBtn.onclick = () => {
renderHistory();
historyPanel.classList.remove('translate-y-full', 'sm:translate-x-full');
};
closeHistory.onclick = () => {
historyPanel.classList.add('translate-y-full', 'sm:translate-x-full');
};
clearHistory.onclick = () => {
localStorage.removeItem('calcHistory');
renderHistory();
};
// Calculator (BODMAS) with sqrt and power support
function calculate(expr) {
try {
// 1️⃣ Handle sqrt → Math.sqrt
expr = expr.replace(/sqrt\s*\(/g, 'Math.sqrt(');
// 2️⃣ Handle power operator ^ → **
expr = expr.replace(/\^/g, '**');
// 3️⃣ Allow safe characters only (numbers, operators, parentheses, dots, Math.sqrt)
const checkExpr = expr.replace(/Math\.sqrt/g, '');
if (/[^0-9+\-*/().\s**]/.test(checkExpr)) {
throw new Error('Invalid characters');
}
// 4️⃣ Evaluate expression safely
const result = Function('"use strict"; return (' + expr + ')')();
// 5️⃣ Handle invalid results
if (typeof result !== 'number' || isNaN(result) || !isFinite(result)) {
return 'Err';
}
// 6️⃣ Round result (optional)
return Number.isInteger(result) ? result : parseFloat(result.toFixed(6));
} catch (err) {
return 'Err';
}
}
// Button click and keyboard support
buttons.forEach(b => {
b.onclick = () => {
const val = b.value;
if (val === '=') {
const res = calculate(screen.value);
if (!isNaN(res)) {
saveHistory(screen.value, res);
screen.value = Number.isInteger(res) ? res : res.toFixed(2);
} else {
screen.value = 'Err';
}
} else if (val === 'C') {
screen.value = '';
} else if (val === '⌫') {
screen.value = screen.value.slice(0, -1);
} else if (val === 'sqrt') {
screen.value += 'sqrt(';
} else if (val === '^') {
screen.value += '^';
} else {
screen.value += val;
}
};
});
document.addEventListener('keydown', e => {
if (/[0-9+\-*/%.()]/.test(e.key)) {
screen.value += e.key;
return;
}
if (e.key === 'Enter' || e.key === '=') {
const res = calculate(screen.value);
if (!isNaN(res)) {
saveHistory(screen.value, res);
screen.value = Number.isInteger(res) ? res : res.toFixed(2);
} else {
screen.value = 'Err';
}
e.preventDefault();
}
if (e.key === 'Backspace') {
screen.value = screen.value.slice(0, -1);
e.preventDefault();
}
if (e.key === '^') {
screen.value += '^';
e.preventDefault();
}
if (e.key.toLowerCase() === 's') {
screen.value += 'sqrt(';
e.preventDefault();
}
if (e.key.toLowerCase() === 'd') {
const newMode = document.documentElement.classList.contains('dark') ? 'light' : 'dark';
setTheme(newMode);
e.preventDefault();
}
if (e.key.toLowerCase() === 'h') {
historyPanel.classList.contains('translate-y-full') || historyPanel.classList.contains('sm:translate-x-full')
? historyPanel.classList.remove('translate-y-full', 'sm:translate-x-full')
: historyPanel.classList.add('translate-y-full', 'sm:translate-x-full');
e.preventDefault();
}
if (e.key.toLowerCase() === 'c') {
screen.value = '';
e.preventDefault();
}
});