Alguém sabe como corrigir esse "Erro no console"

<div id="calc">
    <h3>Calculadora</h3>
    
    <div id="display">
      <div id="previous-display"></div>
      <div id="current-display"></div>
    </div>


    <div id="buttons-container">
      <div class="containerl2">
        <button id="percentual">%</button>
        <button id="limpCalculo">CE</button>
        <button id="limpTudo">C</button>
        <button id="apagar" class="BtnSinais">‹</button>
      </div>


      <div class="containerl3">
        <button id="divisaoUm">1/x</button>
        <button id="potencia">x²</button>
        <button id="raiz">2√x</button>
        <button id="sinaldividir" class="BtnSinais">÷</button>
      </div>


      <div class="containerl4">
        <button id="num7" class="botoes-numericos bgwhite">7</button>
        <button id="num8" class="botoes-numericos bgwhite">8</button>
        <button id="num9" class="botoes-numericos bgwhite">9</button>
        <button id="sinalmultiplica" class="BtnSinais">x</button>
      </div>


      <div class="containerl5">
        <button id="num4" class="botoes-numericos bgwhite">4</button>
        <button id="num5" class="botoes-numericos bgwhite">5</button>
        <button id="num6" class="botoes-numericos bgwhite">6</button>
        <button id="sinalsubtrair" class="BtnSinais">-</button>
      </div>


      <div class="containerl6">
        <button id="num1" class="botoes-numericos bgwhite">1</button>
        <button id="num2" class="botoes-numericos bgwhite">2</button>
        <button id="num3" class="botoes-numericos bgwhite">3</button>
        <button id="sinalsomar" class="BtnSinais">+</button>
      </div>


      <div class="containerl7">
        <button id="maismenos" class="bgwhite">±</button>
        <button id="num0" class="botoes-numericos bgwhite">0</button>
        <button id="virg" class="bgwhite">,</button>
        <button id="igual" class="BtnIgual">=</button>
      </div>
    </div>
  </div>

const previousDisplayText = document.querySelector("#previous-display");
const currentDisplayText = document.querySelector('#current-display')
const buttons = document.querySelectorAll('#buttons-container button')
console.log(buttons);


class Calculator{
  constructor(previousDisplayText, currentDisplayText){
      this.previousDisplayText = previousDisplayText //sempre sai na tela
      this.currentDisplayText = currentDisplayText//sempre sai na tela
      this.currentOperation = "" // valor que o usuário está digitando
  }


  //adicionando digito no display
  addDigit(digit){
      //verificando se já existe "," na operação ou se a mesma está sendo inserida novamente pelo usuário
      if(digit === "," && this.currentDisplayText.innerText.includes(",")){
          return;
      }


      this.currentOperation = digit;
      this.updateScreen();
  }


  // Todas as operações da calculadora
  processOperation(operation){
      //pegar os valores digitados e o operador
      let operationValue;
      const previous = +this.previousDisplayText.innerText;
      const current = +this.currentDisplayText.innerText;


      switch (operation) {
          case "+":
              operationValue = previous + current;
              this.updateScreen(operationValue, operation,current, previous);
              break;
      
          default:
              break;
      }
  }


  // alterando os valores do display
  updateScreen(operationValue = null, operation = null, current = null, previous = null){
      console.log(operationValue, operation, current, previous)        
      this.currentDisplayText.innerText += this.currentOperation;
  }
}


const calc = new Calculator(previousDisplayText, currentDisplayText);


buttons.forEach((btn) => {
  btn.addEventListener("click", (e) =>{
      const value = e.target.innerText;


      if( +value >= 0 || value ===","){
          calc.addDigit(value);
      }else{
          calc.processOperation(value);
      }
  });
})