typedef WebviewViewResolveContext<T>

Persisted state from the webview content.

To save resources, the editor normally deallocates webview documents (the iframe content) that are not visible. For example, when the user collapse a view or switches to another top level activity in the sidebar, the WebviewView itself is kept alive but the webview's underlying document is deallocated. It is recreated when the view becomes visible again.

You can prevent this behavior by setting retainContextWhenHidden in the WebviewOptions. However this increases resource usage and should be avoided wherever possible. Instead, you can use persisted state to save off a webview's state so that it can be quickly recreated as needed.

To save off a persisted state, inside the webview call acquireVsCodeApi().setState() with any json serializable object. To restore the state again, call getState(). For example:

// Within the webview
const vscode = acquireVsCodeApi();
// Get existing state
const oldState = vscode.getState() || { value: 0 };
// Update state
setState({ value: oldState.value + 1 })

The editor ensures that the persisted state is saved correctly when a webview is hidden and across editor restarts.