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script.js
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script.js
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'use strict';
class Calculator {
constructor(previousOperandTextElement, currentOperandTextElement) {
this.previousOperandTextElement = previousOperandTextElement;
this.currentOperandTextElement = currentOperandTextElement;
this.clear();
}
clear() {
this.currentOperand = '';
this.previousOperand = '';
this.operation = undefined;
}
delete() {
this.currentOperand = this.currentOperand.toString().slice(0, -1);
}
appendNumber(number) {
if (number === '.' && this.currentOperand.includes('.')) return;
this.currentOperand = this.currentOperand.toString() + number.toString();
}
chooseOperation(operation) {
if (this.currentOperand === '') return;
if (this.previousOperand !== '') {
this.compute();
}
this.operation = operation;
this.previousOperand = this.currentOperand;
this.currentOperand = '';
}
compute() {
let computation;
const prev = parseFloat(this.previousOperand);
const current = parseFloat(this.currentOperand);
if (isNaN(prev) || isNaN(current)) return;
switch (this.operation) {
case '+':
computation = prev + current;
break;
case '-':
computation = prev - current;
break;
case '÷':
computation = prev / current;
break;
case '*':
computation = prev * current;
break;
default:
return;
}
this.currentOperand = computation;
this.operation = undefined;
this.previousOperand = '';
}
updateDisplay() {
this.currentOperandTextElement.innerText = this.currentOperand;
this.previousOperandTextElement.innerText = this.previousOperand;
}
}
// DOM variables
const previousOperandTextElement = document.querySelector('[data-previous-operand]');
const currentOperandTextElement = document.querySelector('[data-current-operand]');
const numberBtns = document.querySelectorAll('[data-number]');
const operationBtns = document.querySelectorAll('[data-operation]');
const allClearBtn = document.querySelector('[data-all-clear]');
const deleteBtn = document.querySelector('[data-delete]');
const equalsBtn = document.querySelector('[data-equals]');
// Instantiating a new "calculator" object from "Calculator" class
const calculator = new Calculator(previousOperandTextElement, currentOperandTextElement);
// NUMBERS
numberBtns.forEach((button) => {
button.addEventListener('click', () => {
calculator.appendNumber(button.innerText);
calculator.updateDisplay();
});
});
// OPERATORS
operationBtns.forEach((button) => {
button.addEventListener('click', () => {
calculator.chooseOperation(button.innerText);
calculator.updateDisplay();
});
});
// "="
equalsBtn.addEventListener('click', (button) => {
calculator.compute();
calculator.updateDisplay();
});
// AC
allClearBtn.addEventListener('click', (button) => {
calculator.clear();
calculator.updateDisplay();
});
// DEL
deleteBtn.addEventListener('click', (button) => {
calculator.delete();
calculator.updateDisplay();
});
//