consumable-stream

consumable-stream

A readable stream which can be iterated over using a for-await-of loop or using a while loop with await inside.

The ConsumableStream constructor is an abstract class which must be subclassed. Its next() and createConsumer() methods must be overriden.

For a concrete subclass of ConsumableStream, see WritableConsumableStream: https://github.com/SocketCluster/writable-consumable-stream

Installation

npm install consumable-stream

Usage

The ConsumableStream class exposes the following methods:

• [Symbol.asyncIterator]: Makes the instance iterable using a for-await-of loop.
• next: Returns a Promise which will resolve an object in the form {value: data, done: boolean} whenever some data is received or when the stream ends.
• once: Similar to next() except that the resolved value will be the raw data and it will not resolve when the stream ends. Note that once once() is called, it cannot be cancelled; the affected closure will stay in memory until either once() resolves or until the stream is ended or garbage collected.

// Consume data objects from consumableStream as they are written to the stream.
(async () => {
  for await (let data of consumableStream) {
    console.log(data);
  }
})();

// Consume only the next data object which is written to the stream.
(async () => {
  let data = await consumableStream.once();
  console.log(data);
})();