In this tutorial, we will learn how to create a simple Calculator project in JavaScript.
We are going to use vanilla JavaScript to develop this Calculator project.
JavaScript Calculator Project
Create a folder called calculator as project workspace, and we will create all the project files inside this folder.
1. index.html
Let's create index.html and add the following code to it:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Calculator</title>
<link href="style.css" rel="stylesheet">
<script src="script.js" defer></script>
</head>
<body>
<div class="calculator-grid">
<div class="output">
<div data-previous-operand class="previous-operand"></div>
<div data-current-operand class="current-operand"></div>
</div>
<button data-all-clear class="span-two">AC</button>
<button data-delete>DEL</button>
<button data-operation>รท</button>
<button data-number>1</button>
<button data-number>2</button>
<button data-number>3</button>
<button data-operation>*</button>
<button data-number>4</button>
<button data-number>5</button>
<button data-number>6</button>
<button data-operation>+</button>
<button data-number>7</button>
<button data-number>8</button>
<button data-number>9</button>
<button data-operation>-</button>
<button data-number>.</button>
<button data-number>0</button>
<button data-equals class="span-two">=</button>
</div>
</body>
</html>
2. script.js
Let's create a JavaScript file named script.js and add the following JavaScript code to it:
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 'รท':
computation = prev / current
break
default:
return
}
this.currentOperand = computation
this.operation = undefined
this.previousOperand = ''
}
getDisplayNumber(number) {
const stringNumber = number.toString()
const integerDigits = parseFloat(stringNumber.split('.')[0])
const decimalDigits = stringNumber.split('.')[1]
let integerDisplay
if (isNaN(integerDigits)) {
integerDisplay = ''
} else {
integerDisplay = integerDigits.toLocaleString('en', { maximumFractionDigits: 0 })
}
if (decimalDigits != null) {
return `${integerDisplay}.${decimalDigits}`
} else {
return integerDisplay
}
}
updateDisplay() {
this.currentOperandTextElement.innerText =
this.getDisplayNumber(this.currentOperand)
if (this.operation != null) {
this.previousOperandTextElement.innerText =
`${this.getDisplayNumber(this.previousOperand)} ${this.operation}`
} else {
this.previousOperandTextElement.innerText = ''
}
}
}
const numberButtons = document.querySelectorAll('[data-number]')
const operationButtons = document.querySelectorAll('[data-operation]')
const equalsButton = document.querySelector('[data-equals]')
const deleteButton = document.querySelector('[data-delete]')
const allClearButton = document.querySelector('[data-all-clear]')
const previousOperandTextElement = document.querySelector('[data-previous-operand]')
const currentOperandTextElement = document.querySelector('[data-current-operand]')
const calculator = new Calculator(previousOperandTextElement, currentOperandTextElement)
numberButtons.forEach(button => {
button.addEventListener('click', () => {
calculator.appendNumber(button.innerText)
calculator.updateDisplay()
})
})
operationButtons.forEach(button => {
button.addEventListener('click', () => {
calculator.chooseOperation(button.innerText)
calculator.updateDisplay()
})
})
equalsButton.addEventListener('click', button => {
calculator.compute()
calculator.updateDisplay()
})
allClearButton.addEventListener('click', button => {
calculator.clear()
calculator.updateDisplay()
})
deleteButton.addEventListener('click', button => {
calculator.delete()
calculator.updateDisplay()
})
3. style.css
Let's create a CSS file named style.css and add the following CSS code to it:
*, *::before, *::after {
box-sizing: border-box;
font-family: Gotham Rounded, sans-serif;
font-weight: normal;
}
body {
padding: 0;
margin: 0;
background: linear-gradient(to right, #00AAFF, #00FF6C);
}
.calculator-grid {
display: grid;
justify-content: center;
align-content: center;
min-height: 100vh;
grid-template-columns: repeat(4, 100px);
grid-template-rows: minmax(120px, auto) repeat(5, 100px);
}
.calculator-grid > button {
cursor: pointer;
font-size: 2rem;
border: 1px solid white;
outline: none;
background-color: rgba(255, 255, 255, .75);
}
.calculator-grid > button:hover {
background-color: rgba(255, 255, 255, .9);
}
.span-two {
grid-column: span 2;
}
.output {
grid-column: 1 / -1;
background-color: rgba(0, 0, 0, .75);
display: flex;
align-items: flex-end;
justify-content: space-around;
flex-direction: column;
padding: 10px;
word-wrap: break-word;
word-break: break-all;
}
.output .previous-operand {
color: rgba(255, 255, 255, .75);
font-size: 1.5rem;
}
.output .current-operand {
color: white;
font-size: 2.5rem;
}
Open index.html in Browser
Let's open the index.html file in the browser, and you will be able to see the following screen:
More Free JavaScript Projects with Source Code
- JavaScript Tic Tac Toe Game
- JavaScript Project - Modal Box
- JavaScript Project - Modal Box
- JavaScript Project - Password Generator
- JavaScript Project - Weather App
- JavaScript Project - Todo App
- JavaScript Project - Notes App
- JavaScript Project - Movie App
- JavaScript Project - Drawing App
- JavaScript Project - Countdown Timer
- Breakout Game with JavaScript, HTML, and CSS
- Exchange Rate Project with JavaScript, HTML, and CSS
- Expense Tracker Project with JavaScript, HTML, and CSS
- Form Validator with JavaScript, HTML, and CSS
- LyricsSearch App with JavaScript, HTML and CSS
- Movie Seat Booking Project with JavaScript, HTML, and CSS
Comments
Post a Comment