bug(matFormField): Form field state not being updated properly when input dynamically changes
- Dominant language
- TypeScript
- Stars
- 25k
- Forks
- 6.8k
- Avg merge
- 1d 8h
- Merged PRs (30d)
- 91
Description
### Is this a regression?
- [x] Yes, this behavior used to work in the previous version
### The previous version in which this bug was not present was
version 14
### Description
When dynamically changing the input type of a form field, the label and error state of the for field is not properly reflected, the label will not float up and the form outline color will not be set. [See demo example](https://stackblitz.com/edit/nmqf81?file=src%2Fexample%2Fform-field-hint-example.html)
Confirmed that id used to work properly in version 14 [see demo working](https://stackblitz.com/edit/vaqmlj?file=src%2Fapp%2Fform-field-overview-example.ts,src%2Fapp%2Fform-field-overview-example.html)
### Reproduction
Steps to reproduce:
1. open [demo](https://stackblitz.com/edit/nmqf81?file=src%2Fexample%2Fform-field-hint-example.html)
2. toggle slider
3. click submit
4. see that label has not floated and form outline is not red
5. open v14 demo and see it working properly [stackblitz](https://stackblitz.com/edit/vaqmlj?file=src%2Fapp%2Fform-field-overview-example.ts,src%2Fapp%2Fform-field-overview-example.html)
### Expected Behavior
Form field should allow inputs to dynamically change
### Actual Behavior
Error state and label are not propely reflected
### Environment
- Angular: 17
- CDK/Material: 17
Contributor guide
Research direction
Start with the linked StackBlitz reproduction and compare its Angular 17 behavior with the provided version 14 demo while tracing the Angular Material form-field state changes. Reproduce the dynamic input-type toggle and submit flow; done means the label floats and the form outline reflects the error state after the input changes.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- angular, typescript
- Domain
- frontend
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100