# feature:
## In Browser:
- hidden back&forward button in sidebar.
- back and forward is equal with `window.history.back()` `window.history.forward()`
## In Desktop:
- Back and forward can be controlled through the sidebar, cmdk, and shortcut keys.
- back and forward act on the currently **active** view.
- buttons change disable&enable style based on current active view history
# Refactor:
Move app-sidebar and app-container from @affine/component to @affine/core
To support multiple instances, this PR removes some atoms and implements them using the new DI system.
removed atom
- `pageSettingsAtom`
- `currentPageIdAtom`
- `currentModeAtom`
LiveData is a reactive data type.
## basic usage
@example
```ts
const livedata = new LiveData(0); // create livedata with initial value
livedata.next(1); // update value
console.log(livedata.value); // get current value
livedata.subscribe(v => { // subscribe to value changes
console.log(v); // 1
});
```
## observable
LiveData is a rxjs observable, you can use rxjs operators.
@example
```ts
new LiveData(0).pipe(
map(v => v + 1),
filter(v => v > 1),
...
)
```
NOTICE: different from normal observable, LiveData will always emit the latest value when you subscribe to it.
## from observable
LiveData can be created from observable or from other livedata.
@example
```ts
const A = LiveData.from(
of(1, 2, 3, 4), // from observable
0 // initial value
);
const B = LiveData.from(
A.pipe(map(v => 'from a ' + v)), // from other livedata
'' // initial value
);
```
NOTICE: LiveData.from will not complete when the observable completes, you can use `spreadComplete` option to change
this behavior.
## Why is it called LiveData
This API is very similar to LiveData in Android, as both are based on Observable, so I named it LiveData.
EYHN