bug(cdk-virtual-scroll-viewport): If there is not enough data without caching, the scrolling operation will be invalid.
- Dominant language
- TypeScript
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Description
### Is this a regression?
_No response_
### Description
If there is not enough data without caching, the scrolling operation will be invalid.
### Reproduction
StackBlitz link:https://stackblitz.com/edit/angular-sbfsdw?file=src%2Fapp%2Fapp.component.ts,src%2Fapp%2Fng-zorro-antd.module.ts,src%2Fapp%2Fapp.module.ts
Steps to reproduce:
1. If you scroll the mouse in the container, the scroll bar will always react, resulting in unsuccessful scrolling.
2. If you drag the scroll bar directly, you can basically scroll normally, and if the data length is in a certain interval, there will be obvious problems of unsuccessful scrolling.
The core code is as follows:
```
@Component({
selector: 'nz-demo-button-basic',
template: `
`,
styles: [
`
.example-viewport {
height: 600px;
width: 200px;
border: 1px solid black;
}
.example-item {
height: 250px;
border: 1px solid red;
}
`,
],
changeDetection: ChangeDetectionStrategy.OnPush,
})
export class NzDemoButtonBasicComponent {
// length 20000 scroll working
// length 20 scroll no working
items = Array.from({ length: 20 }).map((_, i) => `Item #${i}`);
}
```
### Expected Behavior
No matter the size of itemsize or the amount of data, the scrolling effect is normal.
### Actual Behavior
Unable to scroll up and down
### Environment
- Angular: 16+、18+
- CDK/Material: 16+、18+
- Browser(s):
- Operating System (e.g. Windows, macOS, Ubuntu):
Contributor guide
Research direction
Run the linked StackBlitz reproduction from src/app/app.component.ts with templateCacheSize set to 0 and a short items array. Start at the cdk-virtual-scroll-viewport behavior for insufficient data, then verify scrolling with different item counts and itemSize values. Done means mouse-wheel and scrollbar dragging both scroll normally regardless of data length.
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
- 42/100