I cannot get the html doc to load the javascript to make my calculator working - calculator

Question

I've followed this calculator video on YouTube. I have 3 files in a folder .html, .css & .js.
I open the calculator by double-clicking the HTML file which seems to load up fine in opera with the CSS changing the appearance, however the functionality of the buttons do not work at all. Now I have double-checked the code and even gone as far as cheating with the resource material to be sure it's not an error in the code. I feel that the JavaScript isn't being read/used at all when it loads up.
https://www.youtube.com/watch?v=j59qQ7YWLxw
class calculator {
constructor(perviousOperandTextElement, currentOperandTextElement) {
this.perviousOperandTextElement = perviousOperandTextElement
this.currentOperandTextElement = currentOperandTextElement
this.clear()
}
clear() {
this.currentOperand = ''
this.perviousOperand = ''
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.perviousOperand !== '') {
this.compute()
}
this.operation = operation
this.perviousOperand = 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.perviousOperand = ''
}
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.perviousOperand)} ${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()
})

Answer 1

Your javascript code is wrong at line 67.
We can see that at line 67, your code writes
integerDisplay integerDigits.toLocaleString('en', { maximumFractionDigits: 0 })
This is clearly wrong as you are missing a =, which assigns the value. A solution to this is to replace the line with
integerDisplay = integerDigits.toLocaleString('en', { maximumFractionDigits: 0 })