How to transform `values` object in react-final-form?

Question

I have a situation as follows. I have a class, say MyData.

I'd like to use this with React final form as follows:

<Form
  initialValues={myData} // instance of MyData
  render={({ values }) => /* values should be of type MyData */}
/>

Is this possible, without constructing an instance of MyData on every render? (That would not be ideal, as we're caching some expensive computations.)

I'm not sure what you are requesting. What do you mean by "should be of type MyData"? Are you using TS or Flow? The spread is causing you such "expensive calculations"? — Erik R.
You're right, I could've phrased that better. I ended up doing the following: gist.github.com/rbalicki2/b9b631c831c5870ffc26143fbeed1275 (Instead of using Form from react-final-form, I use this custom Form.) This works just fine for now, but I hadn't thought of this solution when posting this. Thank you! — Robert Balicki

Robert Balicki Robert Balicki · Accepted Answer · 2019-06-13T14:38:47

Looks to not be possible. In final form, we have the following line:

initialValues: initialValues && { ...initialValues },

and as far as I know, it is not possible to override the behavior of the spread operator in this way. This would require changes to final form.

How to transform `values` object in react-final-form?

1 Answers