simple-calculator/main.js at master · catalystcodes/simple-calculator · GitHub

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const randomNo = (max = 255, min = 0) => Math.round(Math.random() * (max - min) + min)

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 = Number(this.previousOperand)
		const current = Number(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 = ''
	}

	getDisplayNumber(number) {
		const stringNumber = number.toString()
		const intergersDigits = Number(stringNumber.split('.')[0])
		const decimalDigits = stringNumber.split('.')[1]
		let intergerDisplay
		if(isNaN(intergersDigits)) {
			intergerDisplay = ''
		} else {
			intergerDisplay = intergersDigits.toLocaleString('en', {maximumFractionDigits:0 })
		}
		if(decimalDigits != null) {
			return `${intergerDisplay}.${decimalDigits}`
		} else {
			return intergerDisplay
		}
	}

	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 allClearButton = document.querySelector('[data-all-clear]')
const deleteButton = document.querySelector('[data-delete]')
const previousOperandTextElement = document.querySelector('[data-previous-operand]')
const currentOperandTextElement = document.querySelector('[data-current-operand]')


setInterval (() => {
	document.querySelector('[catalyst]').style.color = `rgb(${randomNo()}, ${randomNo()}, ${randomNo()})`
},1000)

// setInterval (() => {
// 	document.querySelector('[data-delete]').style.color = `rgb(${randomNo()}, ${randomNo()}, ${randomNo()})`
// },1000)

// setInterval (() => {
// 	document.querySelector('[data-operation]').style.color = `rgb(${randomNo()}, ${randomNo()}, ${randomNo()})`
// },1000)

setInterval (() => {
	document.querySelectorAll(button).style.color = `rgb(${randomNo()}, ${randomNo()}, ${randomNo()})`
},1000)

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()
})