Fast input for number with plus and minus buttons

javascript

(function() {
  function Btn(element, settings) {

    return new Btn.prototype.init(element, settings);
  }

  Btn.prototype.init = function(element, settings) {
    const defaults = {
      min: 0,
      max: 10,
      step: 1,
      start: 1
    }

    const inputRegex = new RegExp(/^\d+$/);

    if (settings) {
      for (let i in defaults) {
        if (settings[i] === undefined)
          settings[i] = defaults[i];
      }
    } else {
      settings = defaults;
    }

    if (settings.min > settings.max) {
      [settings.max, settings.min] = [settings.min, settings.max];
    }

    if (!element) {
      element = document.body;
    }

    const el = document.createElement('div');
    el.classList.add('cButton');

    const plus = document.createElement('button');
    plus.innerText = '+'

    const minus = document.createElement('button');
    minus.innerText = '-'

    const input = document.createElement('input');
    let data = input.value = settings.start;

    el.appendChild(minus);
    el.appendChild(input);
    el.appendChild(plus);


    plus.addEventListener('mousedown', function() {
      data += settings.step;
      timer(plus, '+');
      update();
    });

    minus.addEventListener('mousedown', function() {
      data -= settings.step;
      timer(minus, '-');
      update();
    });

    input.oninput = function(e) {
      if (this.value === '') {
        return;
      }
      if (inputRegex.test(this.value)) {
        data = parseInt(this.value);
        update();
      } else if (this.value.length === 1) {
        data = 0;
        this.value = '';
      }


    };

    input.onchange = function() {
      if (this.value === '') {
        data = settings.start < settings.min ? settings.start : settings.min;
      }

      update();
    }
    this.add = function(n) {
      n = n ? n : 1;
      data = data + n;
      update();
      return this;
    }

    function timer(el, sign) {
      let c_interval;
      let c_timeout;
      let time_interval = 100;
      let step = 1;

      c_timeout = setTimeout(function() {
        c_interval = setInterval(function() {
          if (sign === '+') {
            data += settings.step;
          } else {
            data -= settings.step;
          }
          time_interval = time_interval > 50 ? time_interval - step++ : time_interval;
          update();
        }, time_interval);
      }, 250);

      el.addEventListener('mouseleave', function() {
        clearTimeout(c_timeout);
        clearInterval(c_interval);
      })

      el.addEventListener('mouseup', function() {
        clearTimeout(c_timeout);
        clearInterval(c_interval);
      })
    };

    function update() {
      if (data < settings.min) {
        data = settings.min;
      }

      if (data > settings.max) {
        data = settings.max;
      }

      input.value = data;
    }

    element.appendChild(el);
  }
  window.Btn = Btn;
})()

const $btn = Btn(false, {
  max: 100,
  min: 1,
  start: 50
});