Firesphere / silverstripe-rangefield

import noUiSlider from 'nouislider';

const SETTINGS_ATTR = 'data-settings';

const VALUE_ATTR = 'value';

const SLIDER_CLASS = 'noUi-target';

const ELEMENT_SELECTOR = 'div[data-range=rangefield]';

const observerConfig = {

  attributes: false,

  characterData: false,

  childList: true,

  subtree: true

};

const format = (unit, decimalPlaces) => value => parseFloat(value).toFixed(decimalPlaces) + unit;

const fieldWithName = fieldName => document.body.querySelectorAll(`input[name=${fieldName}]`)[0];

const fieldDescriptionWithName = fieldName => document.body.getElementsByClassName(`${fieldName}-range-description`)[0];

const valueToArray = value => (!Array.isArray(value) ? [value] : value);

const hasFormatSettings = settings => settings.unit && (settings.decimalPlaces > -1);

const updateElementValue = (settings, fieldName, value) => {

  const input = fieldWithName(fieldName);

  const description = fieldDescriptionWithName(fieldName);

  const formatter = format(settings.unit, settings.decimalPlaces);

  const displayValue = hasFormatSettings(settings) ? value.map(formatter) : value;

  input.setAttribute(VALUE_ATTR, displayValue.join(','));

  description.innerHTML = displayValue.join(' ');

};

const mountRangeField = (rangefield) => {

  const fieldName = rangefield.getAttribute(SETTINGS_ATTR);

  const input = fieldWithName(fieldName);

  const settings = window[fieldName];

  settings.start = valueToArray(settings.start);

  if (input.hasAttribute(VALUE_ATTR)) {

    const values = input.getAttribute(VALUE_ATTR).split(',');

    if (values.length === settings.start.length) {

      settings.start = values;

    }

  }

  noUiSlider.create(rangefield, settings);

  rangefield.noUiSlider.on('update', () => {

    const value = valueToArray(rangefield.noUiSlider.get());

    updateElementValue(settings, fieldName, value);

  });

  updateElementValue(settings, fieldName, settings.start);

};

const mount = () => {

  // If things change and we haven't painted our UiSlider yet, go for it

  if (document.body.getElementsByClassName(SLIDER_CLASS).length === 0) {

    const ranges = document.body.querySelectorAll(ELEMENT_SELECTOR);

    ranges.forEach(mountRangeField);

  }

};

const onMutation = () => mount();

/** global: MutationObserver */

const observerFactory = callback => new MutationObserver(callback);

const loadRangeSlider = (createObserver = observerFactory) => {

  mount(); // mount any relevant elements in the dom on load

  createObserver(onMutation).observe(document.body, observerConfig);

};

export default loadRangeSlider;