getFormData - Helper to retrieve fields of a form as an object

getFormData.js

/**
 * Helper to retrieve fields of a form as an object
 */
export const getFormData = form => {
  if (!form || form.tagName !== "FORM") {
    return;
  }

  const { elements } = form;
  const data = {};
  const allowedTags = ["INPUT", "TEXTAREA", "SELECT"];
  const excludedInputTypes = ["button", "reset", "submit"];

  [].slice
    .call(elements)
    .filter(node => allowedTags.indexOf(node.tagName) !== -1 && node.name)
    .forEach(node => {
      if (
        node.tagName === "INPUT" &&
        excludedInputTypes.indexOf(node.type) === -1
      ) {
        if (
          (node.type !== "radio" && node.type !== "checkbox") ||
          (node.type === "radio" && node.checked)
        ) {
          data[node.name] = node.value;
        }
        if (node.type === "checkbox") {
          data[node.name] = node.checked;
        }
      }

      if (node.tagName === "TEXTAREA") {
        data[node.name] = node.value;
      }

      if (node.tagName === "SELECT") {
        const hasOption =
          node.options.length && node.options[node.selectedIndex];
        data[node.name] = hasOption
          ? node.options[node.selectedIndex].value
          : "";
      }
    });
  return data;
};