JSON Field wraps keys around an index key on Save when a key starts with a `.` (period). about payload HOT 1 OPEN

I made an attempt on this, but we have complex interactions in our Forms and I couldn't wrangle this one in the time I had yesterday. I'm posting my findings as a starting point for the next attempt to fix this. I would put this effort into v3 currently the alpha branch at this point.

The function for reducing Fields to values that get sent to the server is here: packages/payload/src/admin/components/forms/Form/reduceFieldsToValues.ts

It calls a utility function called unflatten that we've imported from the flatley package. It is murdering your dot notation by making nested objects. I attempted to fix this by bypassing the unflatten conditionally depending on the field type. This doesn't work because for some reason the fields type has a conditional fieldSchema?: Field property. I don't know why fieldSchema isn't always available, but this function is called from a great many places and at this point I'm not sure if this is the best fix. It might be better to use the form overrides, but I'm not familiar enough with that to take this further.

Here is my logic that doesn't work without fieldSchema sadly:

import { unflatten as flatleyUnflatten } from 'flatley'

import type { Data, Fields } from './types'

/**
 * Reduce flattened form fields (Fields) to just map to the respective values instead of the full FormField object
 *
 * @param unflatten This also unflattens the data if `unflatten` is true. The unflattened data should match the original data structure
 * @param ignoreDisableFormData - if true, will include fields that have `disableFormData` set to true, for example, blocks or arrays fields.
 *
 */
const reduceFieldsToValues = (
  fields: Fields,
  unflatten?: boolean,
  ignoreDisableFormData?: boolean,
): Data => {
  const data = {}
  const unflattenedData = {}

  Object.keys(fields).forEach((key) => {
    if (ignoreDisableFormData === true || !fields[key].disableFormData) {
      if (unflatten && fields[key].fieldSchema?.type === 'json') {
        unflattenedData[key] = fields[key].value
      } else {
        data[key] = fields[key].value
      }
    }
  })

  if (unflatten) {
    return {...flatleyUnflatten(data, { safe: true }), ...unflattenedData}
  }

  return data
}

from payload.