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index.js
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index.js
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let firstNumber = "";
let secondNumber = "";
let currentOperation = null;
let shouldResetScreen = false;
const numberBtns = document.querySelectorAll("[data-number]");
const operatorBtns = document.querySelectorAll("[data-operator]");
const currentScreen = document.querySelector(".current-operation");
const equalsBtn = document.getElementById("equalBtn");
const lastScreen = document.querySelector(".last-operation");
const clearBtn = document.getElementById("btn-clear");
const deleteBtn = document.getElementById("btn-delete");
const pointBtn = document.getElementById("btn-point");
equalsBtn.addEventListener("click", evaluate);
deleteBtn.addEventListener("click", deleteNumber);
operatorBtns.forEach((button) => {
button.addEventListener("click", () => setOperation(button.textContent));
});
numberBtns.forEach((button) => {
button.addEventListener("click", () => {
appendNumber(button.textContent);
});
});
pointBtn.addEventListener("click", appendPoint);
clearBtn.addEventListener("click", clearScreen);
function resetScreen() {
currentScreen.textContent = "";
shouldResetScreen = false;
}
function deleteNumber() {
currentScreen.textContent = currentScreen.textContent.toString().slice(0, -1);
}
function appendPoint() {
if (shouldResetScreen) resetScreen();
if (currentScreen.textContent === "") currentScreen.textContent = "0";
if (currentScreen.textContent.includes(".")) return;
currentScreen.textContent += ".";
}
function appendNumber(num) {
if (currentScreen.textContent === "0" || shouldResetScreen) resetScreen();
currentScreen.textContent += num;
}
function evaluate() {
if (currentOperation === null || shouldResetScreen) return;
if (currentOperation === "÷" && currentScreen.textContent === "0") {
alert("You can't divide by 0!");
return;
}
secondNumber = currentScreen.textContent;
currentScreen.textContent = roundResult(
operate(currentOperation, firstNumber, secondNumber)
);
lastScreen.textContent = `${firstNumber} ${currentOperation} ${secondNumber} =`;
currentOperation = null;
}
function setOperation(operator) {
if (currentOperation !== null) evaluate();
firstNumber = currentScreen.textContent;
currentOperation = operator;
lastScreen.textContent = `${firstNumber} ${currentOperation}`;
shouldResetScreen = true;
}
function roundResult(number) {
return Math.round(number * 1000) / 1000;
}
function add(a, b) {
return a + b;
}
function subtract(a, b) {
return a - b;
}
function multiply(a, b) {
return a * b;
}
function divide(a, b) {
if (b === 0) return "Are you crazy?!";
return a / b;
}
function clearScreen() {
currentScreen.textContent = "0";
lastScreen.textContent = "";
firstNumber = "";
secondNumber = "";
currentOperation = null;
}
function operate(operator, a, b) {
let result;
a = Number(a);
b = Number(b);
switch (operator) {
case "+":
result = add(a, b);
break;
case "-":
result = subtract(a, b);
break;
case "÷":
result = divide(a, b);
break;
case "x":
result = multiply(a, b);
break;
default:
return "Unknown operation!";
}
return result;
}
// module.exports = {
// add,
// subtract,
// divide,
// multiply,
// appendPoint,
// appendNumber,
// deleteNumber,
// };