Type Alias HistoryBlocker

HistoryBlocker: (transaction: HistoryTransaction) => boolean | void

A callback that is called when a history navigation is intended.

Type declaration

- (transaction: HistoryTransaction): boolean | void
- Parameters
  - transaction: HistoryTransaction
    A transaction that describes the intended navigation.
  Returns boolean | void
  true or undefined if the transaction should be blocked until HistoryTransaction.proceed is called, or false if the transaction shouldn't be blocked.

Example

const blocker: HistoryBlocker = transaction => {
  return hasUnsavedChanges && !confirm('Discard unsaved changes?')
};

Example

const blocker: HistoryBlocker = transaction => {
  if (!hasUnsavedChanges) {
    // No unsaved changes, proceed with navigation
    transaction.proceed();
    return;
  }

  if (!confirm('Discard unsaved changes?')) {
    // User decided to keep unsaved changes
    transaction.cancel();
  }
};