to-formdata/index.js

Converts json object/array with image upload to formadata in nested level.

module.exports = (obj, form, namespace) => {
  let fd = form || new FormData();
  let formKey;

  if (!obj || (!Array.isArray(obj) && typeof obj !== 'object')) {
    throw new Error("Please provide valid inputs");
  }

  for (let property in obj) {
    if (obj.hasOwnProperty(property) && obj[property]) {
      if (namespace) {
        formKey = namespace + '[' + property + ']';
      } else {
        formKey = property;
      }

      // if the property is an object, but not a File, use recursivity.
      if (obj[property] instanceof Date) {
        fd.append(formKey, obj[property].toISOString());
      } else if (
        typeof obj[property] === 'object' &&
        !(obj[property] instanceof File)
      ) {
        toFormData(obj[property], fd, formKey);
      } else {
        // if it's a string or a File object
        fd.append(formKey, obj[property]);
      }
    }
  }

  return fd;
}