Nightwatch commands for getting state of multiple elements

getElementsState.js

// Get state for multiple elements
// getState is passed an element and should return a promise that gets some state
// e.g. http://nightwatchjs.org/api#elementIdText
// Callback will be called with an array of the state values once they're all resolved
exports.command = function getElementsState (selector, getState, callback) {
  this.elements('css selector', selector, function (elements) {
    const values = elements.value.map(getState)
    Promise.all(values).then(callback)
  })
  return this
}

getElementsText.js

// Get text for multiple elements
// Callback is called with an array of texts for the matching elements
exports.command = function getElementsText (selector, callback) {
  const getState = (element) => {
    return new Promise((resolve) => {
      this.elementIdText(element.ELEMENT, (text) => resolve(text.value))
    })
  }

  return this.getElementsState(selector, getState, callback)
}

Can you also post sample test for these commands ?.