[ruslan_mart]

Попробуйте:

function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}


var text = ['Text 1', 'Text 2', 'Text 3'];
var input = document.querySelector(".js-chat_input.chat_text_input.form__input.ember-text-area.ember-view");


setTimeout(function fn() {
    input.value = text[getRandomInt(0, text.length - 1)];
    input.form.submit();

    setTimeout(fn, 2000);
}, 2000);