ls-stack utils

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@ls-stack/browser-utils / blockWindowClose

blockWindowClose ​

Functions ​

blockWindowClose() ​

ts
function blockWindowClose(ctx, devTimeoutWarning): object;

Defined in: blockWindowClose.ts:38

Blocks the browser window from closing by setting up a beforeunload handler. This is useful for protecting users from accidentally losing unsaved work.

The function supports multiple simultaneous blocks using contexts, and only removes the beforeunload handler when all blocks are removed. It also includes development-time warnings to help detect memory leaks from undisposed blocks.

Important: This should be used sparingly and only when necessary, as it can negatively impact user experience. Always ensure blocks are properly disposed of.

Parameters ​

ctx ​

Unique context identifier for this block. If not provided, an auto-increment ID is used

string | number

devTimeoutWarning ​

number = 120_000

Time in milliseconds after which to show a development warning (default: 120,000ms / 2 minutes)

Returns ​

object

An object with unblock method and Symbol.dispose for cleanup

[dispose]() ​
ts
[dispose]: () => void;
Returns ​

void

unblock ​
ts
unblock: VoidFunction;

Example ​

ts
// Basic usage - block window close during form editing
const blocker = blockWindowClose();

// Later, when form is saved or user cancels
blocker.unblock();