## Types ### StreamsHandlerCallback() ```typescript workbox-streams.StreamsHandlerCallback(   __namedParameters: RouteHandlerCallbackOptions, ): StreamSource | Promise ``` #### Parameters - __namedParameters [RouteHandlerCallbackOptions](https://developer.chrome.com/docs/workbox/workbox-core/#type-RouteHandlerCallbackOptions) #### Returns - [StreamSource](https://developer.chrome.com/docs/workbox/modules/workbox-streams#type-StreamSource) \| Promise\<[StreamSource](https://developer.chrome.com/docs/workbox/modules/workbox-streams#type-StreamSource)\> ### StreamSource #### Enum Response ReadableStream BodyInit
## Methods ### concatenate() ```typescript workbox-streams.concatenate(   sourcePromises: Promise[], ): object ``` Takes multiple source Promises, each of which could resolve to a Response, a ReadableStream, or a [BodyInit](https://fetch.spec.whatwg.org/#bodyinit). Returns an object exposing a ReadableStream with each individual stream's data returned in sequence, along with a Promise which signals when the stream is finished (useful for passing to a FetchEvent's waitUntil()). #### Parameters - sourcePromises Promise\<[StreamSource](https://developer.chrome.com/docs/workbox/modules/workbox-streams#type-StreamSource)\>\[\] #### Returns - object > } ### concatenateToResponse() ```typescript workbox-streams.concatenateToResponse(   sourcePromises: Promise[],   headersInit: HeadersInit, ): object ``` Takes multiple source Promises, each of which could resolve to a Response, a ReadableStream, or a [BodyInit](https://fetch.spec.whatwg.org/#bodyinit), along with a [HeadersInit](https://fetch.spec.whatwg.org/#typedefdef-headersinit). Returns an object exposing a Response whose body consists of each individual stream's data returned in sequence, along with a Promise which signals when the stream is finished (useful for passing to a FetchEvent's waitUntil()). #### Parameters - sourcePromises Promise\<[StreamSource](https://developer.chrome.com/docs/workbox/modules/workbox-streams#type-StreamSource)\>\[\] - headersInit HeadersInit #### Returns - object > } ### isSupported() ```typescript workbox-streams.isSupported(): boolean ``` This is a utility method that determines whether the current browser supports the features required to create streamed responses. Currently, it checks if [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream/ReadableStream) can be created. #### Returns - boolean `true`, if the current browser meets the requirements for streaming responses, and `false` otherwise. ### strategy() ```typescript workbox-streams.strategy(   sourceFunctions: StreamsHandlerCallback[],   headersInit: HeadersInit, ): RouteHandlerCallback ``` A shortcut to create a strategy that could be dropped-in to Workbox's router. On browsers that do not support constructing new `ReadableStream`s, this strategy will automatically wait for all the `sourceFunctions` to complete, and create a final response that concatenates their values together. #### Parameters - sourceFunctions [StreamsHandlerCallback](https://developer.chrome.com/docs/workbox/modules/workbox-streams#method-StreamsHandlerCallback)\[\] - headersInit HeadersInit #### Returns - [RouteHandlerCallback](https://developer.chrome.com/docs/workbox/workbox-core/#method-RouteHandlerCallback)