getFormElementValue() - Returns the value of a form element, given it's name and type

getFormElementValue.js

/**
 * getFormElementValue()
 *  Returns the value of a form element, given it's name and type
 *
 * @param {String} name - An element's `name=""` attribute
 * @param {String} type - An element type string, e.g. 'text', 'radio', 'select'
 * @returns {String|Boolean}
 */
const getFormElementValue = (function(){
  const getElement = name => document.querySelector('[name="' + name + '"]');
  const getters = {};
  getters.text = name => getElement(name).value;
  getters.checkbox = name => getElement(name).checked;
  getters.radio = name => {
    const elems = document.getElementsByName(name);
    for (var i = 0; i < elems.length; i++) {
      if (elems[i].checked) return elems[i].value;
    }
  }
  getters.select = name => {
    var elem = getElement(name);
    return elem.options[elem.selectedIndex].value;
  };
  return (name, type) => getters[type](name);
}());

getFormElementValue('field-text', 'text');           //=> String (value attr)
getFormElementValue('field-radio', 'radio');         //=> String (value attr) | undefined
getFormElementValue('field-checkbox-1', 'checkbox'); //=> Boolean
getFormElementValue('field-checkbox-2', 'checkbox'); //=> Boolean
getFormElementValue('field-select', 'select');       //=> String (value attr)