Код: Выделить всё
let runningTotal = 0;
let buffer = "0";
let previousOperator;**strong text**
const screen = document.querySelector(".screen");
function buttonClick(value) {
if (isNaN(parseInt(value))) {
handleSymbol(value);
} else {
handleNumber(value);
}
rerender();
}
function handleNumber(value) {
if (buffer === "0") {
buffer = value;
} else {
buffer += value;
}
}
function handleMath(value) {
if (buffer === "0") {
// do nothing
return;
}
const intBuffer = parseInt(buffer);
if (runningTotal === 0) {
runningTotal = intBuffer;
} else {
flushOperation(intBuffer);
}
previousOperator = value;
buffer = "0";
}
function flushOperation(intBuffer) {
if (previousOperator === "+") {
runningTotal += intBuffer;
} else if (previousOperator === "-") {
runningTotal -= intBuffer;
} else if (previousOperator === "×") {
runningTotal *= intBuffer;
} else {
runningTotal /= intBuffer;
}
}
function handleSymbol(value) {
switch (value) {
case "C":
buffer = "0";
runningTotal = 0;
break;
case "=":
if (previousOperator === null) {
// need two numbers to do math
return;
}
flushOperation(parseInt(buffer));
previousOperator = null;
buffer = +runningTotal;
runningTotal = 0;
break;
case "←":
if (buffer.length === 1) {
buffer = "0";
} else {
buffer = buffer.substring(0, buffer.length - 1);
}
break;
case "+":
case "-":
case "×":
case "÷":
handleMath(value);
break;
}
}
function rerender() {
screen.innerText = buffer;
}
function init() {
document
.querySelector(".calc-buttons")
.addEventListener("click", function (event) {
buttonClick(event.target.innerText);
});
}
init();
Подробнее здесь: https://stackoverflow.com/questions/739 ... g-anything
Мобильная версия