How to make an HTML input field not accepting successive identical chars when the key is being pressed

Question

I have an HTML input field but if the user keeps on pressing a key, it will add the same letter non-stop. I want to suppress this behavior.

How can I override the input component's input event listener to not allow to not add successive characters when the key is being kept pressed down?

Answer 1

<input type="text" oninput="this.value = this.value.replace(/(.)\1+/g, '$1')" />

https://jsfiddle.net/sxwr2u3z/

Answer 2

Another answer. This one uses KeyboardEvent.repeat to detect continuous pressing.

const input = document.querySelector('input');

input.addEventListener('input', function (event) {
    this.value = this.value.replace(/.$/,'');
});
input.addEventListener('keyup', function (event) {
    if (event.repeat) return;
  this.value += event.key;
});