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Observe PDF Document Editor visibility | Nutrient

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If you need to be notified when Document Editor is displayed or hidden, use the viewState.change event listener to check whether or not Document Editor is being displayed:

// Add the event listener to the instance.
instance.addEventListener(
  "viewState.change",
  (viewState, previousState) => {
    // Check if the current view state is "document_editor."
    if (
      viewState.interactionMode?.toLowerCase() === "document_editor"
    ) {
      console.log("Document Editor Displaying");
    }
    // If the previous view state is "document_editor," the document editor was closed.
    if (
      previousState.interactionMode?.toLowerCase() === "document_editor"
    ) {
      console.log("Document Editor Hidden");
    }
  }
);

This has been tested with Nutrient Web SDK 2020.6.4.