JSFiddle - React, Tailwind, and code Playground

HTML

<button id="first">First</button>
<button id="second">Second</button>

JavaScript

function runOnce( callback ) {
  
  var done = false;
  
  return function() {
    if ( !done ) {
      done = true;
    
      callback();
    }
  };
  
}

var one = runOnce(function() { alert('Once'); }),
    two = runOnce(function() { alert('Once only too.'); });

document.getElementById('first').onclick = one;
document.getElementById('second').onclick = two;