JSFiddle - React, Tailwind, and code Playground

by dandrade78

HTML

<textarea id="ta" rows="4" cols="50">
 ABC
 DEF
 GHI
 </textarea>
 <input type="text" id="rt" name="textnumber" value="">

JavaScript

var tarea = document.querySelector('#ta')
var input = document.querySelector('#rt')

function update() {
  var res = (tarea.value.match(/\n/g)) ? tarea.value.match(/\n/g).length : 0;
  //                 ^^^^^^
  //          this is a ternary (like a conditional check)
  input.value = res;
}

tarea.addEventListener('input', update) 	// ERRO NESTA LINHA