js calculator

calculator.js

let outputValue = document.getElementById('output');
let numbers = document.querySelectorAll('.num-btn');
let decimal = document.getElementById('dec-btn')
let operators = document.querySelectorAll('.op-btn');
let equals = document.getElementById('equal-btn');
let clear = document.getElementById('clear');
let inputValue = [];

function add(num1, num2) {
	return num1 + num2;
}

function subtract(num1, num2) {
	return num1 - num2;
}

function multiply(num1, num2) {
	return num1 * num2;
}

function divide(num1, num2) {
	return num1 / num2;
}

function sqrt(num1) {
	Math.sqrt(num1);
}

function operate(operator, num1, num2) {

	switch (operator) {
		case "+":
			outputValue.innerHTML = add(num1, num2);
			break;
		case "-":
			outputValue.innerHTML = subtract(num1, num2);
			break;
		case "*":
			outputValue.innerHTML = multiply(num1, num2);
			break;
		case "/":
			outputValue.innerHTML = divide(num1, num2);
			break;
		case "sqrt":
			outputValue.innerHTML = sqrt(num1);
			break;
	}
}

numbers.forEach((number) => {
	number.addEventListener('click', output);
});

decimal.addEventListener('click', output);

operators.forEach((operator) => {
	operator.addEventListener('click', output);
});

function output(event) {
	
	inputValue.push(event.target.innerHTML);

	if (inputValue.indexOf('.') > -1) decimal.removeEventListener('click', output);

	let reg = /(\d+)([+/*-])(\d+)/;
	let match = reg.exec(inputValue.join(""));

	let num1 = match[1];
	let operator = match[2];
	let num2 = match[3];
	
	outputValue.innerHTML = num1 + ' ' + operator + ' ' + num2;

	equals.addEventListener('click', operate(operator, num1, num2));
}