javascript class event-listener queryselector

Getting textcontent from multiple elements individually using one class name

I am developing a calculator as a part of the frontEndMasters course but I cannot get the numbers to work, number seven only works. I would like to know if there is any workaround for this since I thought that I could also write an eventlistener for every button but that would violate DRY.

const screens = document.querySelector(".screen");
const clearing = document.querySelector(".calc-buttonBigC");
const buttons = document.querySelector(".calc-button");

console.log(screens.textContent);

clearing.addEventListener('click', () =>{
    screens.textContent = "";
});

 buttons.addEventListener('click', () =>{
    screens.textContent += buttons.textContent;
});

<div class='calc'>
  <section class='screen'>
    
  </section>
<section class='calc-buttons'>
<div class='row'>
  <button class='calc-buttonBigC'>C</button>
  <button class='calc-button-spec'>◄</button>
  <button class='calc-button-spec'>/</button>
</div>
  <div class='row'>
       <button class='calc-button'>7</button>
      <button class='calc-button'>8</butbutton>
      <button class='calc-button'>9</button>
      <button class='calc-button-spec'>x</button>
    </div>
  <div class='row'>
      <button class='calc-button'>4</button>
      <button class='calc-button'>5</button>
      <button class='calc-button'>6</button>
      <button class='calc-button-spec'>-</button>
    </div>
    <div class='row'>
      <button class='calc-button'>1</button>
      <button class='calc-button'>2</button>
      <button class='calc-button'>3</button>
      <button class='calc-button-spec'>+</button>
    </div>
  <div class='row'>
      <button class='calc-buttonBig'>0</button>
      <button class='calc-button-spec'>=</button>
    </div>
  </section>
</div>

I have used querySelector and querySelectorAll with the numbers but I only get the number seven to work.

As far as I understand I have to use a for each loop to get all the numbers to work.

Any suggestions ?

Thank you.

Solution

You are using querySelector(".calc-button"), which looks for the first element that matches the supplied selector and that element is the 7 button in your case. If you want to handle all the buttons, you have to set up an event handler for each, use querySelectorAll() and then loop over each reference in handler, or (preferably) use "event delegation" to set up one handler for all the buttons and then reference the specific element that triggered the event using the .target property of the event.

Here's an example to get you back on track:

const screens = document.querySelector(".screen");
const clearing = document.querySelector(".calc-buttonBigC");

// Get a reference to an ancestor element of all the buttons
const calc = document.querySelector(".calc");

clearing.addEventListener('click', () =>{
    screens.textContent = "";
});

// When any of the descendent elements get clicked,
// the event will bubble up to the ancestor and be
// handled here.
calc.addEventListener('click', function(event){
  // The event reference is automatically passed to
  // the handler and you use the .target property of
  // the event to get a reference to the element that
  // originated the event.
    
  // First, determine if the event was triggered by
  // an element you care to handle.
  if(event.target.classList.contains("calc-button")) {
    // Then work with the element
    screens.textContent += event.target.textContent;
  }
});

<div class='calc'>
  <section class='screen'></section>
  <section class='calc-buttons'>
  <div class='row'>
    <button class='calc-buttonBigC'>C</button>
    <button class='calc-button-spec'>◄</button>
    <button class='calc-button-spec'>/</button>
  </div>
  <div class='row'>
      <button class='calc-button'>7</button>
      <button class='calc-button'>8</butbutton>
      <button class='calc-button'>9</button>
      <button class='calc-button-spec'>x</button>
    </div>
  <div class='row'>
      <button class='calc-button'>4</button>
      <button class='calc-button'>5</button>
      <button class='calc-button'>6</button>
      <button class='calc-button-spec'>-</button>
    </div>
    <div class='row'>
      <button class='calc-button'>1</button>
      <button class='calc-button'>2</button>
      <button class='calc-button'>3</button>
      <button class='calc-button-spec'>+</button>
    </div>
  <div class='row'>
      <button class='calc-buttonBig'>0</button>
      <button class='calc-button-spec'>=</button>
    </div>
  </section>
</div>