marmelab/react-admin

UseWatch with an input field that has a default value returns undefined when the input field is not changed

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#9,419 opened on Nov 3, 2023

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Description

What you were expecting: I would expect that useWatch returns the default value of the field.

What happened instead: useWatch returns undefined, untill I change the watched field.

Steps to reproduce:

create a form with an input that has a default value, then have another component use useWatch on that input field, the resulting value is undefined untill you change the input.

Related code: I created a WatchBug component in the PostCreate file. It watches the Published at input. you see that initally the value returned is undefined. https://stackblitz.com/edit/github-mjvobu?file=src%2Fposts%2FPostCreate.tsx

Environment

  • React-admin version: 4.15.2
  • Last version that did not exhibit the issue (if applicable): 4.8.4 does not show the bug, I did not try other versions inbetween.

Working version on 4.8.4 https://stackblitz.com/edit/github-ladv9x?file=src%2Fposts%2FPostCreate.tsx

Contributor guide

Research direction
Inspect the useWatch hook implementation in react admin, specifically how it initializes values from form defaults. Compare versions 4.8.4 and 4.15.2 to identify the change that caused the regression. Focus on the logic that retrieves the initial value before any user interaction.
Tech stack
typescriptreact
Domain
frontend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
ReactTypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75