[feature]not removing field name from state, when its value become empty

In all examples if write something in input, than clear it, the field name will be dropped from state. But is it possibly maybe with some additional prop like notRemoveWhenEmpty in Field, the value will be null, or empty or anything else.

[petermikitsh]

In the meantime, I’ve wrote a simple adapter for the Field component, and my application code imports this adapter component in place of the official one:

import {Field} from 'react-final-form';
import React from 'react';

const identity = value => (value);

/* This wraps react-final-form's <Field/> component.
 * The identity function ensures form values never get set to null,
 * but rather, empty strings.
 *
 * See https://github.com/final-form/react-final-form/issues/130
 */
export default props => <Field parse={identity} {...props}/>;

[petermikitsh]

The fact that parse, by default, isn’t an identity function (e.g., value => (value)) is not what I would expect. @erikras, thoughts?

I can speak to my use case (maybe it applies to others-- I am migrating from redux-form, but I don’t want to sound like a special snowflake, either). I have an existing record I am editing via HTTP PATCH. The field in question cannot be null – this is enforced at the database level. If a user clears the field, it will be null, and thus its key will be set to undefined in the onSubmit function. (Analogously, I believe it would have been an empty string in redux-form).

By the time the object makes it to my ORM and ultimately becomes a SQL statement, the deleted property isn’t included in the UPDATE sql statement. So the HTTP PATCH request successfully executes. The user then assumes the request is valid, but if they refresh the page, they would see the value they attempted to delete is still there. The fact that the user had entered an empty string in the text input was valuable – I used that to throw an error.

Again, this might be my personal super snowflake use case, but I’m curious if it’s something others have encountered. Maybe this is more of an issue with my ORM neglecting to attempt passing the undefined value.