Auto Growing text-area [Stimulus] [Rails]

_form.html.erb

<!-- Some form -->  
  <div data-controller="auto-grow-textarea">
    <%= form.text_area :body, cols: 20, row: 2, placeholder: 'Bir yorum yazın...', class:'form-control', data: { action: 'input->auto-grow-textarea#resize', target: 'auto-grow-textarea.input' } %>
  </div>
<!-- Some form continued --> 

auto-grow-textarea_controller.js

import {Controller} from "stimulus";

export default class extends Controller {
    static targets = ["input"];

    connect() {
        console.log('auto-grow-textarea controller connected...');
        this.inputTarget.style.resize = 'none';
        this.inputTarget.style.minHeight = `${this.inputTarget.scrollHeight}px`;
    }

    resize(event){
        event.target.style.height = '5px';
        event.target.style.height =  `${event.target.scrollHeight}px`;
    }

}

Small improvement: you can add this.inputTarget.style.overflow = 'hidden'; at the end of the connect method to prevent the scrollbar from appearing when adding text.

Well, I made it in the CSS but it's a nice tip! It might help others. Thanks, @goulvench.