ReadableStream DefaultReader
Background
A reader is used when you want to read from a ReadableStream, rather than piping its output to a WritableStream.
A ReadableStreamDefaultReader is not instantiated via its constructor. Rather, it is retrieved from a ReadableStream:
const { readable, writable } = new TransformStream();const reader = readable.getReader();Properties
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reader.closed: Promise- A promise indicating if the reader is closed. The promise is fulfilled when the reader stream closes and is rejected if there is an error in the stream.
Methods
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read(): Promise- A promise that returns the next available chunk of data being passed through the reader queue.
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cancel(reasonstringoptional): void- Cancels the stream.
reasonis an optional human-readable string indicating the reason for cancellation.reasonwill be passed to the underlying source’s cancel algorithm — if this readable stream is one side of aTransformStream, then its cancel algorithm causes the transform’s writable side to become errored withreason.
- Cancels the stream.
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releaseLock(): void- Releases the lock on the readable stream. A lock cannot be released if the reader has pending read operations. A
TypeErroris thrown and the reader remains locked.
- Releases the lock on the readable stream. A lock cannot be released if the reader has pending read operations. A