setHeaderValue method

JSPromise<JSAny?> setHeaderValue(String value)

The setHeaderValue() method of the NavigationPreloadManager interface sets the value of the header that will be sent with requests resulting from a fetch operation made during service worker navigation preloading. It returns an empty Promise that resolves with undefined.

The presence of the header in preloading requests allows servers to configure the returned resource differently for preloading fetch requests than from normal fetch requests. The default directive is set to true: this method allows the possibility of configuring multiple different responses to preload requests.

Note: If a different response may result from setting this header, the server must set Vary: Service-Worker-Navigation-Preload to ensure that the different responses are cached.

Implementation

external JSPromise<JSAny?> setHeaderValue(String value);