Подсчет количества символов в тектовом поле

      .field-counter-words {
    font-size: 12px;
    color: #808080;
    margin-left: 8px;
}
.field-counter-words.is-error {
    color: red;
}
    

      document.addEventListener('DOMContentLoaded', CountingLengthWords);
    function CountingLengthWords() {
        const fieldInput = document.querySelector('form#SaveRecord input[name="command[data][general][name]"]');
        let fieldCounter = null;
        let counterCurrent = null;

        const NUMBER_CHARACTERS_TOTAL = 128;
        let number_characters_current = 0;

        if (fieldInput) {

            function setCounterOnLoadPage() {
                counterCurrent.innerText = fieldInput.value.length;
            }

            function validateCounter() {
                if (number_characters_current >= NUMBER_CHARACTERS_TOTAL) {
                    addError();
                } else {
                    removeError();
                }
            }

            function addError() {
                fieldCounter.classList.add('is-error');
            }

            function removeError() {
                if (fieldCounter.classList.contains('is-error')) {
                    fieldCounter.classList.remove('is-error');
                }
            }

            function insertHtmlTemplateCounter() {
                fieldInput.insertAdjacentHTML('afterend', `<span class="field-counter-words"><span class="field-counter-words__current">0</span>/<span class="field-counter-words__total">${NUMBER_CHARACTERS_TOTAL}</span></span>`);
                fieldCounter = fieldInput.parentNode.querySelector('.field-counter-words');
            }

            function handlerOnInputFieldName(e) {
                fieldInput.value = fieldInput.value.slice(0,NUMBER_CHARACTERS_TOTAL);
                number_characters_current = e.target.value.length;
                counterCurrent.innerText = e.target.value.length;
                validateCounter();
            }

            insertHtmlTemplateCounter();

            if (fieldCounter) {
                counterCurrent = document.querySelector('.field-counter-words__current');
                fieldInput.addEventListener('input', handlerOnInputFieldName);
                setCounterOnLoadPage();
            }

        }

    }