Return promise for readable stream
npm install promise-readable
This module allows to convertReadable
stream into its promisified version, which returnsPromise
object fulfilled when open,data,close,end orerror events
occurred.
The promisified stream provides an async iterator so it is possible to use it
with for await...of
statement.
This module requires Node >= 16.
``shell`
npm install promise-readable
_Additionally for Typescript:_
`shell`
npm install -D @types/node
`js`
import PromiseReadable from "promise-readable"
`js`
const promiseReadable = new PromiseReadable(stream)
PromiseReadable object requires Readable object to work.
_Example:_
`js
import fs from "node:fs"
import PromiseReadable from "promise-readable"
const stream = fs.createReadStream("/etc/hosts")
const promiseReadable = new PromiseReadable(stream)
`
`js`
const stream = promiseReadable.stream
Original stream object.
_Example:_
`js`
console.log(promiseReadable.stream.flags)
`js`
const chunk = await promiseReadable.read(chunkSize)
This method returns Promise which is fulfilled when the stream can returnread
one chunk (by method or data event) or the stream is ended (end orclose events).
_Example:_
`js`
const chunk = await promiseReadable.read(1024)
Promise returns chunk data if something has been read or undefined value if
it is an end of the stream.
_Example:_
`js`
for (let chunk; (chunk = await promiseReadable.read()); ) {
console.log(chunk.length)
}
console.log("stream is ended")
`js`
const content = await promiseReadable.readAll()
This method returns Promise which is fulfilled when the stream is ended orundefined
closed. It is resolved to value if the stream is already ended or
closed.
The content from the stream is buffered and then Promise returns this
concatenated content.
`js`
promiseReadable = promiseReadable.setEncoding(encoding)
By default read and readAll methods return Buffer objects.
This method sets the character encoding for data read from the stream. It
might be used if the original stream does not provide encoding option.
The method returns this object.
_Example:_
`js
const asBuffer = await promiseReadable.read()
promiseReadable.setEncoding("utf8")
const asString = await promiseReadable.read()
`
`js`
const result = await promiseReadable.once(event)
This method returns Promise which is fulfilled when the stream emitsevent. The result of this event is returned or undefined` value if the
stream has already ended.
The promise will be rejected on error.
_Example:_
`js
const fd = await promiseReadable.once("open")
promiseReadable.stream.pipe(process.stdout)
await promiseReadable.once("close")
promiseReadable.stream.on("data", chunk => console.log(chunk.length))
await promiseReadable.once("end")
await promiseReadable.once("error") // throws error, undefined if ended
`
`js`
for await (const chunk of promiseReadable.iterate(chunkSize)) {
}
This method returns an async iterator which returns the content of the stream
chunk-by-chunk with a defined chunkSize.
`js`
for await (const chunk of promiseReadable) {
}
The PromiseReadable object is an async iterator that returns the content ofchunkSize
the stream chunk-by-chunk with the default .
`js`
promiseReadable = promiseReadable.destroy()
This method calls destroy method on stream and cleans up all own handlers.
The method returns this object.
PromiseWritable,
PromiseDuplex,
PromiseSocket,
PromisePiping`.
Copyright (c) 2017-2024 Piotr Roszatycki