Reservair/assets/js/forms/RsvFormEncoder.js

export const RsvFormEncoder = {
  // Serialize form element into a plain JS object supporting arrays.
  // - Nested keys supported with dot notation: 'meta.email'
  // - Array notation supported with trailing [] (e.g. 'times[]') or multiple inputs with same name
  encode_form(form_element) {
    const formData = new FormData(form_element);
    const body = {};

    for (const [rawKey, value] of formData.entries()) {
      const isArrayNotation = rawKey.endsWith('[]');
      const key = isArrayNotation ? rawKey.slice(0, -2) : rawKey;
      const keys = key.split('.');

      let current = body;
      for (let i = 0; i < keys.length - 1; i++) {
        const k = keys[i];
        if (current[k] === undefined || typeof current[k] !== 'object') {
          current[k] = {};
        }
        current = current[k];
      }

      const lastKey = keys[keys.length - 1];

      if (isArrayNotation) {
        if (!Array.isArray(current[lastKey])) current[lastKey] = [];
        current[lastKey].push(value);
      } else {
        if (current[lastKey] === undefined) {
          current[lastKey] = value;
        } else if (Array.isArray(current[lastKey])) {
          current[lastKey].push(value);
        } else {
          current[lastKey] = [current[lastKey], value];
        }
      }
    }

    return body;
  }
}