bug(mat-date-range-picker): When used with angular forms, `valueChanges` is fired multiple times.
Open
area: material/datepicker
P3
- Dominant language
- TypeScript
- Stars
- 25k
- Forks
- 6.8k
- Avg merge
- 1d 8h
- Merged PRs (30d)
- 91
Description
#### Expected Behavior
Observable should emit only once per change
#### Actual Behavior
When listening on the `formGroup`, it fires 4 times, and when listening on `start` or `end` it fires 2 times
#### Bug demo
https://stackblitz.com/edit/angular-date-range-bug
#### Environment
- Angular: 10
- CDK/Material: 10
Contributor guide
Research direction
Start with the linked StackBlitz reproduction and compare valueChanges emissions from the formGroup, start, and end controls in the Angular 10 date-range-picker example. Trace the date range picker’s interaction with Angular forms, then verify that each change emits once at all three levels.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- angular, typescript
- Domain
- frontend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100