Vanilla-JavaScript-Calculator-starter/calculator.js at master · coleymal/Vanilla-JavaScript-Calculator-starter · GitHub

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class Calculator {
    constructor(previousOperandTextElement, currentOperandTextElement) {
      this.previousOperandTextElement = previousOperandTextElement
      this.currentOperandTextElement = currentOperandTextElement
      this.clear()
    }

    chooseOperation(operation) {

    }

    compute() {

    }

    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()
    }

    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 = ''
      }
    }
  }