Namespace Events

Example

// Listen for view state changes
instance.addEventListener("viewState.change", (viewState, previousViewState) => {
  console.log("View state changed:", viewState.toJS());
});

// Listen for annotation creation
instance.addEventListener("annotations.create", (annotations) => {
  console.log("New annotations created:", annotations.toJS());
});

// Listen for page navigation
instance.addEventListener("viewState.currentPageIndex.change", (pageIndex) => {
  console.log("Current page changed to:", pageIndex);
});
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Event Handler Types

Each event has a corresponding event listener type that defines the expected function signature. These types ensure type safety when registering event listeners and provide clear documentation of the parameters each event listener receives.

Event Lifecycle

Many events follow a lifecycle pattern:

• Will events: Fired before an action occurs, allowing you to prevent it
• Change events: Fired when the state changes
• Did events: Fired after an action completes

For example, with annotations:

• annotations.willSave → annotations.change → annotations.didSave