angular / angular/components

bug(snackbar): Snackbar appears twice when loading on app start

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#28,601 1 comment 0 reactions 0 assignees View on GitHub
area: material/snack-bar P5
Dominant language
TypeScript
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Description

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

Snackbar appears twice - once without animation, and once with. I could only see this when showing the snackbar in my root component. Please manually scrub the videos to see the two states.

https://github.com/angular/components/assets/4698762/1a0fe6a8-2c2b-4489-b18e-97208b79d1b9

https://github.com/angular/components/assets/4698762/f71b3034-6fbe-4e61-aea2-b99e8a49b47d

Showing snackbar later works fine, as seen on docs: https://material.angular.io/components/snack-bar/examples.

### Reproduction

StackBlitz link: https://stackblitz.com/edit/stackblitz-starters-shuyqd?file=src%2Fmain.ts

Steps to reproduce:

1. Load snackbar in root component
2. Reload

### Expected Behavior

Snackbar should appear once, gracefully with fade-in animation. It does so when not loading in root component.

### Actual Behavior

Snackbar appears once without animation and then fade-in animation kicks in.

### Environment

- Angular: 17.2.1
- CDK/Material: 17.2.0
- Browser(s): Consistently on Firefox and Safari, sometimes on Chrome
- Operating System (e.g. Windows, macOS, Ubuntu):

Contributor guide

Open the contributing guide

Research direction

Start with the linked StackBlitz reproduction, especially src/main.ts, and reload it in Firefox or Safari to confirm the duplicate snackbar states. Trace the root-component startup behavior and compare it with showing the snackbar later. Done means the snackbar appears only once with its fade-in animation.

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

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