Serialize all form data into a JSON string

serializeJSON.js

/**
 * Serialize all form data into a JSON string.
 * https://gist.github.com/kieranbarker/98f8dadbf824236e42820419b1da58eb
 * @param {HTMLFormElement} form The form to serialize.
 * @returns {string} The serialized form data.
 */
function serializeJSON (form) {
  // Create a new FormData object
  const formData = new FormData(form);

  // Create an object to hold the name/value pairs
  const pairs = {};

  // Add each name/value pair to the object
  for (const [name, value] of formData) {
    pairs[name] = value;
  }

  // Return the JSON string
  return JSON.stringify(pairs);
}

Read the blog post:

https://kbarker.dev/blog/serialize-form-data-into-a-json-string-in-vanilla-js/

View the demo:

https://codepen.io/kieranbarker/pen/XWjPYvr